1 ." Copyright (c) 1994, 2012, Oracle and/or its affiliates. All rights reserved.

     1 '\" t

     2 ." DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     2 .\"  Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.

     3 ."

     3 .\"

     4 ." This code is free software; you can redistribute it and/or modify it

     4 .\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     5 ." under the terms of the GNU General Public License version 2 only, as

     5 .\"

     6 ." published by the Free Software Foundation.

     6 .\" This code is free software; you can redistribute it and/or modify it

     7 ."

     7 .\" under the terms of the GNU General Public License version 2 only, as

     8 ." This code is distributed in the hope that it will be useful, but WITHOUT

     8 .\" published by the Free Software Foundation.

     9 ." ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

     9 .\"

    10 ." FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    10 .\" This code is distributed in the hope that it will be useful, but WITHOUT

    11 ." version 2 for more details (a copy is included in the LICENSE file that

    11 .\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    12 ." accompanied this code).

    12 .\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License

    13 ."

    13 .\" version 2 for more details (a copy is included in the LICENSE file that

    14 ." You should have received a copy of the GNU General Public License version

    14 .\" accompanied this code).

    15 ." 2 along with this work; if not, write to the Free Software Foundation,

    15 .\"

    16 ." Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    16 .\" You should have received a copy of the GNU General Public License version

    17 ."

    17 .\" 2 along with this work; if not, write to the Free Software Foundation,

    18 ." Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    18 .\" Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    19 ." or visit www.oracle.com if you need additional information or have any

    19 .\"

    20 ." questions.

    20 .\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    21 ."

    21 .\" or visit www.oracle.com if you need additional information or have any

    22 .TH javac 1 "10 May 2011"

    22 .\" questions.

    23 

    23 .\"

    24 .LP

    24 .\"     Arch: generic

    25 .SH "Name"

    25 .\"     Software: JDK 8

    26 javac \- Java programming language compiler

    26 .\"     Date: 21 November 2013

    27 .LP

    27 .\"     SectDesc: Basic Tools

    28 .SH "SYNOPSIS"

    28 .\"     Title: javac.1

    29 .LP

    29 .\"

    30 .nf

    30 .if n .pl 99999

    31 \f3

    31 .TH javac 1 "21 November 2013" "JDK 8" "Basic Tools"

    32 .fl

    32 .\" -----------------------------------------------------------------

    33         \fP\f3javac\fP [ options ] [ sourcefiles ] [ classes ] [ @argfiles ]

    33 .\" * Define some portability stuff

    34 .fl

    34 .\" -----------------------------------------------------------------

    35 

    35 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    36 .fl

    36 .\" http://bugs.debian.org/507673

    37 .fi

    37 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html

    38 

    38 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    39 .LP

    39 .ie \n(.g .ds Aq \(aq

    40 .LP

    40 .el       .ds Aq '

    41 Arguments may be in any order.

    41 .\" -----------------------------------------------------------------

    42 .LP

    42 .\" * set default formatting

    43 .RS 3

    43 .\" -----------------------------------------------------------------

    44 .TP 3

    44 .\" disable hyphenation

    45 .nh

    46 .\" disable justification (adjust text to left margin only)

    47 .ad l

    48 .\" -----------------------------------------------------------------

    49 .\" * MAIN CONTENT STARTS HERE *

    50 .\" -----------------------------------------------------------------

    51 

    52 .SH NAME    

    53 javac \- Reads Java class and interface definitions and compiles them into bytecode and class files\&.

    54 .SH SYNOPSIS    

    55 .sp     

    56 .nf     

    57 

    58 \fBjavac\fR [ \fIoptions\fR ] [ \fIsourcefiles\fR ] [ \fIclasses\fR] [ \fI@argfiles\fR ]

    59 .fi     

    60 .sp     

    61 Arguments can be in any order:

    62 .TP     

    63 \fIoptions\fR

    64 Command-line options\&. See Options\&.

    65 .TP     

    66 \fIsourcefiles\fR

    67 One or more source files to be compiled (such as \f3MyClass\&.java\fR)\&.

    68 .TP     

    69 \fIclasses\fR

    70 One or more classes to be processed for annotations (such as \f3MyPackage\&.MyClass\fR)\&.

    71 .TP     

    72 \fI@argfiles\fR

    73 One or more files that list options and source files\&. The \f3-J\fR options are not allowed in these files\&. See Command-Line Argument Files\&.

    74 .SH DESCRIPTION    

    75 The \f3javac\fR command reads class and interface definitions, written in the Java programming language, and compiles them into bytecode class files\&. The \f3javac\fR command can also process annotations in Java source files and classes\&.

    76 .PP

    77 There are two ways to pass source code file names to \f3javac\fR\&.

    78 .TP 0.2i    

    79 \(bu

    80 For a small number of source files, list the file names on the command line\&.

    81 .TP 0.2i    

    82 \(bu

    83 For a large number of source files, list the file names in a file that is separated by blanks or line breaks\&. Use the list file name preceded by an at sign (@) with the \f3javac\fR command\&.

    84 .PP

    85 Source code file names must have \&.java suffixes, class file names must have \&.class suffixes, and both source and class files must have root names that identify the class\&. For example, a class called \f3MyClass\fR would be written in a source file called \f3MyClass\&.java\fR and compiled into a bytecode class file called \f3MyClass\&.class\fR\&.

    86 .PP

    87 Inner class definitions produce additional class files\&. These class files have names that combine the inner and outer class names, such as \f3MyClass$MyInnerClass\&.class\fR\&.

    88 .PP

    89 Arrange source files in a directory tree that reflects their package tree\&. For example, if all of your source files are in \f3/workspace\fR, then put the source code for \f3com\&.mysoft\&.mypack\&.MyClass\fR in \f3/workspace/com/mysoft/mypack/MyClass\&.java\fR\&.

    90 .PP

    91 By default, the compiler puts each class file in the same directory as its source file\&. You can specify a separate destination directory with the \f3-d\fR option\&.

    92 .SH OPTIONS    

    93 The compiler has a set of standard options that are supported on the current development environment\&. An additional set of nonstandard options are specific to the current virtual machine and compiler implementations and are subject to change in the future\&. Nonstandard options begin with the \f3-X\fR option\&.

    94 .TP 0.2i    

    95 \(bu

    96 See also Cross-Compilation Options

    97 .TP 0.2i    

    98 \(bu

    99 See also Nonstandard Options

   100 .SS STANDARD\ OPTIONS    

   101 .TP

   102 -A\fIkey\fR[\fI=value\fR]

   103 .br

   104 Specifies options to pass to annotation processors\&. These options are not interpreted by \f3javac\fR directly, but are made available for use by individual processors\&. The \f3key\fR value should be one or more identifiers separated by a dot (\&.)\&.

   105 .TP

   106 -cp \fIpath\fR or -classpath \fIpath\fR

   107 .br

   108 Specifies where to find user class files, and (optionally) annotation processors and source files\&. This class path overrides the user class path in the \f3CLASSPATH\fR environment variable\&. If neither \f3CLASSPATH\fR, \f3-cp\fR nor \f3-classpath\fR is specified, then the user \fIclass path\fR is the current directory\&. See Setting the Class Path\&.

   109 

   110 If the \f3-sourcepath\fR option is not specified, then the user class path is also searched for source files\&.

   111 

   112 If the \f3-processorpath\fR option is not specified, then the class path is also searched for annotation processors\&.

   113 .TP

   114 -Djava\&.ext\&.dirs=\fIdirectories\fR

   115 .br

   116 Overrides the location of installed extensions\&.

   117 .TP

   118 -Djava\&.endorsed\&.dirs=\fIdirectories\fR

   119 .br

   120 Overrides the location of the endorsed standards path\&.

   121 .TP

   122 -d \fIdirectory\fR

   123 .br

   124 Sets the destination directory for class files\&. The directory must already exist because \f3javac\fR does not create it\&. If a class is part of a package, then \f3javac\fR puts the class file in a subdirectory that reflects the package name and creates directories as needed\&.

   125 

   126 If you specify \f3-d\fR\f3/home/myclasses\fR and the class is called \f3com\&.mypackage\&.MyClass\fR, then the class file is \f3/home/myclasses/com/mypackage/MyClass\&.class\fR\&.

   127 

   128 If the \fI-d\fR option is not specified, then \f3javac\fR puts each class file in the same directory as the source file from which it was generated\&.

   129 

   130 \fINote:\fR The directory specified by the \fI-d\fR option is not automatically added to your user class path\&.

   131 .TP

   132 -deprecation

   133 .br

   134 Shows a description of each use or override of a deprecated member or class\&. Without the \f3-deprecation\fR option, \f3javac\fR shows a summary of the source files that use or override deprecated members or classes\&. The \f3-deprecation\fR option is shorthand for \f3-Xlint:deprecation\fR\&.

   135 .TP

   136 -encoding \fIencoding\fR

   137 .br

   138 Sets the source file encoding name, such as EUC-JP and UTF-8\&. If the \f3-encoding\fR option is not specified, then the platform default converter is used\&.

   139 .TP

   140 -endorseddirs \fIdirectories\fR

   141 .br

   142 Overrides the location of the endorsed standards path\&.

   143 .TP

   144 -extdirs \fIdirectories\fR

   145 .br

   146 Overrides the location of the \f3ext\fR directory\&. The directories variable is a colon-separated list of directories\&. Each JAR file in the specified directories is searched for class files\&. All JAR files found become part of the class path\&.

   147 

   148 If you are cross-compiling (compiling classes against bootstrap and extension classes of a different Java platform implementation), then this option specifies the directories that contain the extension classes\&. See Cross-Compilation Options for more information\&.

   149 .TP

   150 -g

   151 .br

   152 Generates all debugging information, including local variables\&. By default, only line number and source file information is generated\&.

   153 .TP

   154 -g:none

   155 .br

   156 Does not generate any debugging information\&.

   157 .TP

   158 -g:[\fIkeyword list\fR]

   159 .br

   160 Generates only some kinds of debugging information, specified by a comma separated list of keywords\&. Valid keywords are:

   161 .RS     

   162 .TP     

   163 source

   164 Source file debugging information\&.

   165 .TP     

   166 lines

   167 Line number debugging information\&.

   168 .TP     

   169 vars

   170 Local variable debugging information\&.

   171 .RE     

   172 

   173 .TP

   174 -help

   175 .br

   176 Prints a synopsis of standard options\&.

   177 .TP

   178 -implicit:[\fIclass, none\fR]

   179 .br

   180 Controls the generation of class files for implicitly loaded source files\&. To automatically generate class files, use \f3-implicit:class\fR\&. To suppress class file generation, use \f3-implicit:none\fR\&. If this option is not specified, then the default is to automatically generate class files\&. In this case, the compiler issues a warning if any such class files are generated when also doing annotation processing\&. The warning is not issued when the \f3-implicit\fR option is set explicitly\&. See Searching for Types\&.

   181 .TP

   182 -J\fIoption\fR

   183 .br

   184 Passes \f3option\fR to the Java Virtual Machine (JVM), where option is one of the options described on the reference page for the Java launcher\&. For example, \f3-J-Xms48m\fR sets the startup memory to 48 MB\&. See java(1)\&.

   185 

   186 \fINote:\fR The \fICLASSPATH\fR, \f3-classpath\fR, \f3-bootclasspath\fR, and \f3-extdirs\fR options do not specify the classes used to run \f3javac\fR\&. Trying to customize the compiler implementation with these options and variables is risky and often does not accomplish what you want\&. If you must customize the complier implementation, then use the \f3-J\fR option to pass options through to the underlying \f3\fRJava launcher\&.

   187 .TP

   188 -nowarn

   189 .br

   190 Disables warning messages\&. This option operates the same as the \f3-Xlint:none\fR option\&.

   191 .TP

   192 -parameters

   193 .br

   194 Stores formal parameter names of constructors and methods in the generated class file so that the method \f3java\&.lang\&.reflect\&.Executable\&.getParameters\fR from the Reflection API can retrieve them\&.

   195 .TP

   196 -proc: [\fInone\fR, \fIonly\fR]

   197 .br

   198 Controls whether annotation processing and compilation are done\&. \f3-proc:none\fR means that compilation takes place without annotation processing\&. \f3-proc:only\fR means that only annotation processing is done, without any subsequent compilation\&.

   199 .TP

   200 -processor \fIclass1\fR [,\fIclass2\fR,\fIclass3\fR\&.\&.\&.]

   201 .br

   202 Names of the annotation processors to run\&. This bypasses the default discovery process\&.

   203 .TP

   204 -processorpath \fIpath\fR

   205 .br

   206 Specifies where to find annotation processors\&. If this option is not used, then the class path is searched for processors\&.

   207 .TP

   208 -s \fIdir\fR

   209 .br

   210 Specifies the directory where to place the generated source files\&. The directory must already exist because \f3javac\fR does not create it\&. If a class is part of a package, then the compiler puts the source file in a subdirectory that reflects the package name and creates directories as needed\&.

   211 

   212 If you specify \f3-s /home/mysrc\fR and the class is called \f3com\&.mypackage\&.MyClass\fR, then the source file is put in \f3/home/mysrc/com/mypackage/MyClass\&.java\fR\&.

   213 .TP

   214 -source \fIrelease\fR

   215 .br

   216 Specifies the version of source code accepted\&. The following values for \f3release\fR are allowed:

   217 .RS     

   218 .TP     

   219 1\&.3

   220 The compiler does not support assertions, generics, or other language features introduced after Java SE 1\&.3\&.

   221 .TP     

   222 1\&.4

   223 The compiler accepts code containing assertions, which were introduced in Java SE 1\&.4\&.

   224 .TP     

   225 1\&.5

   226 The compiler accepts code containing generics and other language features introduced in Java SE 5\&.

   227 .TP     

   228 5

   229 Synonym for 1\&.5\&.

   230 .TP     

   231 1\&.6

   232 No language changes were introduced in Java SE 6\&. However, encoding errors in source files are now reported as errors instead of warnings as in earlier releases of Java Platform, Standard Edition\&.

   233 .TP     

   234 6

   235 Synonym for 1\&.6\&.

   236 .TP     

   237 1\&.7

   238 This is the default value\&. The compiler accepts code with features introduced in Java SE 7\&.

   239 .TP     

   240 7

   241 Synonym for 1\&.7\&.

   242 .RE     

   243 

   244 .TP

   245 -sourcepath \fIsourcepath\fR

   246 .br

   247 Specifies the source code path to search for class or interface definitions\&. As with the user class path, source path entries are separated by colons (:) on Oracle Solaris and semicolons on Windows and can be directories, JAR archives, or ZIP archives\&. If packages are used, then the local path name within the directory or archive must reflect the package name\&.

   248 

   249 \fINote:\fR Classes found through the class path might be recompiled when their source files are also found\&. See Searching for Types\&.

   250 .TP

   251 -verbose

   252 .br

   253 Uses verbose output, which includes information about each class loaded and each source file compiled\&.

   254 .TP

   255 -version

   256 .br

   257 Prints release information\&.

   258 .TP

   259 -werror

   260 .br

   261 Terminates compilation when warnings occur\&.

   262 .TP

   263 -X

   264 .br

   265 Displays information about nonstandard options and exits\&.

   266 .SS CROSS-COMPILATION\ OPTIONS    

   267 By default, classes are compiled against the bootstrap and extension classes of the platform that \f3javac\fR shipped with\&. But \f3javac\fR also supports cross-compiling, where classes are compiled against a bootstrap and extension classes of a different Java platform implementation\&. It is important to use the \f3-bootclasspath\fR and \f3-extdirs\fR options when cross-compiling\&.

   268 .TP

   269 -target \fIversion\fR

   270 .br

   271 Generates class files that target a specified release of the virtual machine\&. Class files will run on the specified target and on later releases, but not on earlier releases of the JVM\&. Valid targets are 1\&.1, 1\&.2, 1\&.3, 1\&.4, 1\&.5 (also 5), 1\&.6 (also 6), and 1\&.7 (also 7)\&.

   272 

   273 The default for the \f3-target\fR option depends on the value of the \f3-source\fR option:

   274 .RS     

   275 .TP 0.2i    

   276 \(bu

   277 If the \f3-source\fR option is not specified, then the value of the \f3-target\fR option is 1\&.7

   278 .TP 0.2i    

   279 \(bu

   280 If the \f3-source\fR option is 1\&.2, then the value of the \f3-target\fR option is 1\&.4

   281 .TP 0.2i    

   282 \(bu

   283 If the \f3-source\fR option is 1\&.3, then the value of the \f3-target\fR option is 1\&.4

   284 .TP 0.2i    

   285 \(bu

   286 If the \f3-source\fR option is 1\&.5, then the value of the \f3-target\fR option is 1\&.7

   287 .TP 0.2i    

   288 \(bu

   289 If the \f3-source\fR option is 1\&.6, then the value of the \f3-target\fR is option 1\&.7

   290 .TP 0.2i    

   291 \(bu

   292 For all other values of the \f3-source\fR option, the value of the \f3-target\fR option is the value of the \f3-source\fR option\&.

   293 .RE     

   294 

   295 .TP

   296 -bootclasspath \fIbootclasspath\fR

   297 .br

   298 Cross-compiles against the specified set of boot classes\&. As with the user class path, boot class path entries are separated by colons (:) and can be directories, JAR archives, or ZIP archives\&.

   299 .SS COMPACT\ PROFILE\ OPTION    

   300 Beginning with JDK 8, the \f3javac\fR compiler supports compact profiles\&. With compact profiles, applications that do not require the entire Java platform can be deployed and run with a smaller footprint\&. The compact profiles feature could be used to shorten the download time for applications from app stores\&. This feature makes for more compact deployment of Java applications that bundle the JRE\&. This feature is also useful in small devices\&.

   301 .PP

   302 The supported profile values are \f3compact1\fR, \f3compact2\fR, and \f3compact3\fR\&. These are additive layers\&. Each higher-numbered compact profile contains all of the APIs in profiles with smaller number names\&.

   303 .TP

   304 -profile

   305 .br

   306 When using compact profiles, this option specifies the profile name when compiling\&. For example:

   307 .sp     

   308 .nf     

   309 \f3javac \-profile compact1 Hello\&.java\fP

   310 .fi     

   311 .nf     

   312 \f3\fP

   313 .fi     

   314 .sp     

   315 

   316 

   317 javac does not compile source code that uses any Java SE APIs that is not in the specified profile\&. Here is an example of the error message that results from attempting to compile such source code:

   318 .sp     

   319 .nf     

   320 \f3cd jdk1\&.8\&.0/bin\fP

   321 .fi     

   322 .nf     

   323 \f3\&./javac \-profile compact1 Paint\&.java\fP

   324 .fi     

   325 .nf     

   326 \f3Paint\&.java:5: error: Applet is not available in profile \&'compact1\&'\fP

   327 .fi     

   328 .nf     

   329 \f3import java\&.applet\&.Applet;\fP

   330 .fi     

   331 .nf     

   332 \f3\fP

   333 .fi     

   334 .sp     

   335 

   336 

   337 In this example, you can correct the error by modifying the source to not use the \f3Applet\fR class\&. You could also correct the error by compiling without the -profile option\&. Then the compilation would be run against the full set of Java SE APIs\&. (None of the compact profiles include the \f3Applet\fR class\&.)

   338 

   339 An alternative way to compile with compact profiles is to use the \f3-bootclasspath\fR option to specify a path to an \f3rt\&.jar\fR file that specifies a profile\&'s image\&. Using the \f3-profile\fR option instead does not require a profile image to be present on the system at compile time\&. This is useful when cross-compiling\&.

   340 .SS NONSTANDARD\ OPTIONS    

   341 .TP

   342 -Xbootclasspath/p:\fIpath\fR

   343 .br

   344 Adds a suffix to the bootstrap class path\&.

   345 .TP

   346 -Xbootclasspath/a:\fIpath\fR

   347 .br

   348 Adds a prefix to the bootstrap class path\&.

   349 .TP

   350 -Xbootclasspath/:\fIpath\fR

   351 .br

   352 Overrides the location of the bootstrap class files\&.

   353 .TP

   354 -Xdoclint:[-]\fIgroup\fR [\fI/access\fR]

   355 .br

   356 Enables or disables specific groups of checks, where \fIgroup\fR is one of the following values: \f3accessibility\fR, \f3syntax\fR, \f3reference\fR, \f3html\fR or \f3missing\fR\&. For more information about these groups of checks see the \f3-Xdoclint\fR option of the \f3javadoc\fR command\&. The \f3-Xdoclint\fR option is disabled by default in the \f3javac\fR command\&.

   357 

   358 The variable \fIaccess\fR specifies the minimum visibility level of classes and members that the \f3-Xdoclint\fR option checks\&. It can have one of the following values (in order of most to least visible) : \f3public\fR, \f3protected\fR, \f3package\fR and \f3private\fR\&. For example, the following option checks classes and members (with all groups of checks) that have the access level protected and higher (which includes protected, package and public):

   359 .sp     

   360 .nf     

   361 \f3\-Xdoclint:all/protected\fP

   362 .fi     

   363 .nf     

   364 \f3\fP

   365 .fi     

   366 .sp     

   367 

   368 

   369 The following option enables all groups of checks for all access levels, except it will not check for HTML errors for classes and members that have access level package and higher (which includes package and public):

   370 .sp     

   371 .nf     

   372 \f3\-Xdoclint:all,\-html/package\fP

   373 .fi     

   374 .nf     

   375 \f3\fP

   376 .fi     

   377 .sp     

   378 

   379 .TP

   380 -Xdoclint:none

   381 .br

   382 Disables all groups of checks\&.

   383 .TP

   384 -Xdoclint:all[\fI/access\fR]

   385 .br

   386 Enables all groups of checks\&.

   387 .TP

   388 -Xlint

   389 .br

   390 \fI\fREnables all recommended warnings\&. In this release, enabling all available warnings is recommended\&.

   391 .TP

   392 -Xlint:all

   393 .br

   394 \fI\fREnables all recommended warnings\&. In this release, enabling all available warnings is recommended\&.

   395 .TP

   396 -Xlint:none

   397 .br

   398 Disables all warnings\&.

   399 .TP

   400 -Xlint:\fIname\fR

   401 .br

   402 Disables warning name\&. See Enable or Disable Warnings with the -Xlint Option for a list of warnings you can disable with this option\&.

   403 .TP

   404 -Xlint:\fI-name\fR

   405 .br

   406 Disables warning name\&. See Enable or Disable Warnings with the -Xlint Option with the \f3-Xlint\fR option to get a list of warnings that you can disable with this option\&.

   407 .TP

   408 -Xmaxerrs \fInumber\fR

   409 .br

   410 Sets the maximum number of errors to print\&.

   411 .TP

   412 -Xmaxwarns \fInumber\fR

   413 .br

   414 Sets the maximum number of warnings to print\&.

   415 .TP

   416 -Xstdout \fIfilename\fR

   417 .br

   418 Sends compiler messages to the named file\&. By default, compiler messages go to \f3System\&.err\fR\&.

   419 .TP

   420 -Xprefer:[\fInewer,source\fR]

   421 .br

   422 Specifies which file to read when both a source file and class file are found for a type\&. (See Searching for Types)\&. If the \f3-Xprefer:newer\fR option is used, then it reads the newer of the source or class file for a type (default)\&. If the \f3-Xprefer:source\fR option is used, then it reads the source file\&. Use -\f3Xprefer:source\fR when you want to be sure that any annotation processors can access annotations declared with a retention policy of \f3SOURCE\fR\&.

   423 .TP

   424 -Xpkginfo:[\fIalways\fR,\fIlegacy\fR,\fInonempty\fR]

   425 .br

   426 Control whether javac generates \f3package-info\&.class\fR files from package-info\&.java files\&. Possible mode arguments for this option include the following\&.

   427 .RS     

   428 .TP     

   429 always

   430 Always generate a \f3package-info\&.class\fR file for every \f3package-info\&.java\fR file\&. This option may be useful if you use a build system such as Ant, which checks that each \f3\&.java\fR file has a corresponding \f3\&.class\fR file\&.

   431 .TP     

   432 legacy

   433 Generate a \f3package-info\&.class\fR file only if package-info\&.java contains annotations\&. Don\&'t generate a \f3package-info\&.class\fR file if package-info\&.java only contains comments\&.

   434 

   435 \fINote:\fR A \f3package-info\&.class\fR file might be generated but be empty if all the annotations in the package-info\&.java file have \f3RetentionPolicy\&.SOURCE\fR\&.

   436 .TP     

   437 nonempty

   438 Generate a \f3package-info\&.class\fR file only if package-info\&.java contains annotations with \f3RetentionPolicy\&.CLASS\fR or \f3RetentionPolicy\&.RUNTIME\fR\&.

   439 .RE     

   440 

   441 .TP

   442 -Xprint

   443 .br

   444 Prints a textual representation of specified types for debugging purposes\&. Perform neither annotation processing nor compilation\&. The format of the output could change\&.

   445 .TP

   446 -XprintProcessorInfo

   447 .br

   448 Prints information about which annotations a processor is asked to process\&.

   449 .TP

   450 -XprintRounds

   451 .br

   452 Prints information about initial and subsequent annotation processing rounds\&.

   453 .SH ENABLE\ OR\ DISABLE\ WARNINGS\ WITH\ THE\ -XLINT\ OPTION    

   454 Enable warning \fIname\fR with the \f3-Xlint:name\fR option, where \f3name\fR is one of the following warning names\&. Note that you can disable a warning with the \f3-Xlint:-name:\fR option\&.

   455 .TP     

   456 cast

   457 Warns about unnecessary and redundant casts, for example:

   458 .sp     

   459 .nf     

   460 \f3String s = (String) "Hello!"\fP

   461 .fi     

   462 .nf     

   463 \f3\fP

   464 .fi     

   465 .sp     

   466 

   467 .TP     

   468 classfile

   469 Warns about issues related to class file contents\&.

   470 .TP     

   471 deprecation

   472 Warns about the use of deprecated items, for example:

   473 .sp     

   474 .nf     

   475 \f3java\&.util\&.Date myDate = new java\&.util\&.Date();\fP

   476 .fi     

   477 .nf     

   478 \f3int currentDay = myDate\&.getDay();\fP

   479 .fi     

   480 .nf     

   481 \f3\fP

   482 .fi     

   483 .sp     

   484 

   485 

   486 The method \f3java\&.util\&.Date\&.getDay\fR has been deprecated since JDK 1\&.1

   487 .TP     

   488 dep-ann

   489 Warns about items that are documented with an \f3@deprecated\fR Javadoc comment, but do not have a \f3@Deprecated\fR annotation, for example:

   490 .sp     

   491 .nf     

   492 \f3/**\fP

   493 .fi     

   494 .nf     

   495 \f3  * @deprecated As of Java SE 7, replaced by {@link #newMethod()}\fP

   496 .fi     

   497 .nf     

   498 \f3  */\fP

   499 .fi     

   500 .nf     

   501 \f3public static void deprecatedMethood() { }\fP

   502 .fi     

   503 .nf     

   504 \f3public static void newMethod() { }\fP

   505 .fi     

   506 .nf     

   507 \f3\fP

   508 .fi     

   509 .sp     

   510 

   511 .TP     

   512 divzero

   513 Warns about division by the constant integer 0, for example:

   514 .sp     

   515 .nf     

   516 \f3int divideByZero = 42 / 0;\fP

   517 .fi     

   518 .nf     

   519 \f3\fP

   520 .fi     

   521 .sp     

   522 

   523 .TP     

   524 empty

   525 Warns about empty statements after \f3if\fRstatements, for example:

   526 .sp     

   527 .nf     

   528 \f3class E {\fP

   529 .fi     

   530 .nf     

   531 \f3    void m() {\fP

   532 .fi     

   533 .nf     

   534 \f3         if (true) ;\fP

   535 .fi     

   536 .nf     

   537 \f3    }\fP

   538 .fi     

   539 .nf     

   540 \f3}\fP

   541 .fi     

   542 .nf     

   543 \f3\fP

   544 .fi     

   545 .sp     

   546 

   547 .TP     

   548 fallthrough

   549 Checks the switch blocks for fall-through cases and provides a warning message for any that are found\&. Fall-through cases are cases in a switch block, other than the last case in the block, whose code does not include a break statement, allowing code execution to fall through from that case to the next case\&. For example, the code following the case 1 label in this switch block does not end with a break statement:

   550 .sp     

   551 .nf     

   552 \f3switch (x) {\fP

   553 .fi     

   554 .nf     

   555 \f3case 1:\fP

   556 .fi     

   557 .nf     

   558 \f3  System\&.out\&.println("1");\fP

   559 .fi     

   560 .nf     

   561 \f3  // No break statement here\&.\fP

   562 .fi     

   563 .nf     

   564 \f3case 2:\fP

   565 .fi     

   566 .nf     

   567 \f3  System\&.out\&.println("2");\fP

   568 .fi     

   569 .nf     

   570 \f3}\fP

   571 .fi     

   572 .nf     

   573 \f3\fP

   574 .fi     

   575 .sp     

   576 

   577 

   578 If the \f3-Xlint:fallthrough\fR option was used when compiling this code, then the compiler emits a warning about possible fall-through into case, with the line number of the case in question\&.

   579 .TP     

   580 finally

   581 Warns about \f3finally\fR clauses that cannot complete normally, for example:

   582 .sp     

   583 .nf     

   584 \f3public static int m() {\fP

   585 .fi     

   586 .nf     

   587 \f3  try {\fP

   588 .fi     

   589 .nf     

   590 \f3     throw new NullPointerException();\fP

   591 .fi     

   592 .nf     

   593 \f3  }  catch (NullPointerException(); {\fP

   594 .fi     

   595 .nf     

   596 \f3     System\&.err\&.println("Caught NullPointerException\&.");\fP

   597 .fi     

   598 .nf     

   599 \f3     return 1;\fP

   600 .fi     

   601 .nf     

   602 \f3   } finally {\fP

   603 .fi     

   604 .nf     

   605 \f3     return 0;\fP

   606 .fi     

   607 .nf     

   608 \f3   }\fP

   609 .fi     

   610 .nf     

   611 \f3  }\fP

   612 .fi     

   613 .nf     

   614 \f3\fP

   615 .fi     

   616 .sp     

   617 

   618 

   619 The compiler generates a warning for the \f3finally\fR block in this example\&. When the \f3int\fR method is called, it returns a value of 0\&. A \f3finally\fR block executes when the \f3try\fR block exits\&. In this example, when control is transferred to the \f3catch\fR block, the \f3int\fR method exits\&. However, the \f3finally\fR block must execute, so it is executed, even though control was transferred outside the method\&.

   620 .TP     

    46 Command\-line options.

   622 Warns about issues that related to the use of command-line options\&. See Cross-Compilation Options\&.

    47 .TP 3

   623 .TP     

    48 sourcefiles

   624 overrides

    49 One or more source files to be compiled (such as MyClass.java).

   625 Warns about issues regarding method overrides\&. For example, consider the following two classes:

    50 .TP 3

   626 .sp     

    51 classes

   627 .nf     

    52 One or more classes to be processed for annotations (such as MyPackage.MyClass).

   628 \f3public class ClassWithVarargsMethod {\fP

    53 .TP 3

   629 .fi     

    54 @argfiles

   630 .nf     

    55 One or more files that lists options and source files. The \f2\-J\fP options are not allowed in these files.

   631 \f3  void varargsMethod(String\&.\&.\&. s) { }\fP

   632 .fi     

   633 .nf     

   634 \f3}\fP

   635 .fi     

   636 .nf     

   637 \f3\fP

   638 .fi     

   639 .nf     

   640 \f3public class ClassWithOverridingMethod extends ClassWithVarargsMethod {\fP

   641 .fi     

   642 .nf     

   643 \f3   @Override\fP

   644 .fi     

   645 .nf     

   646 \f3   void varargsMethod(String[] s) { }\fP

   647 .fi     

   648 .nf     

   649 \f3}\fP

   650 .fi     

   651 .nf     

   652 \f3\fP

   653 .fi     

   654 .sp     

   655 

   656 

   657 The compiler generates a warning similar to the following:\&.

   658 .sp     

   659 .nf     

   660 \f3warning: [override] varargsMethod(String[]) in ClassWithOverridingMethod \fP

   661 .fi     

   662 .nf     

   663 \f3overrides varargsMethod(String\&.\&.\&.) in ClassWithVarargsMethod; overriding\fP

   664 .fi     

   665 .nf     

   666 \f3method is missing \&'\&.\&.\&.\&'\fP

   667 .fi     

   668 .nf     

   669 \f3\fP

   670 .fi     

   671 .sp     

   672 

   673 

   674 When the compiler encounters a \f3varargs\fR method, it translates the \f3varargs\fR formal parameter into an array\&. In the method \f3ClassWithVarargsMethod\&.varargsMethod\fR, the compiler translates the \f3varargs\fR formal parameter \f3String\&.\&.\&. s\fR to the formal parameter \f3String[] s\fR, an array, which matches the formal parameter of the method \f3ClassWithOverridingMethod\&.varargsMethod\fR\&. Consequently, this example compiles\&.

   675 .TP     

   676 path

   677 Warns about invalid path elements and nonexistent path directories on the command line (with regard to the class path, the source path, and other paths)\&. Such warnings cannot be suppressed with the \f3@SuppressWarnings\fR annotation, for example:

   678 .sp     

   679 .nf     

   680 \f3javac \-Xlint:path \-classpath /nonexistentpath Example\&.java\fP

   681 .fi     

   682 .nf     

   683 \f3\fP

   684 .fi     

   685 .sp     

   686 

   687 .TP     

   688 processing

   689 Warn about issues regarding annotation processing\&. The compiler generates this warning when you have a class that has an annotation, and you use an annotation processor that cannot handle that type of exception\&. For example, the following is a simple annotation processor:

   690 

   691 \fISource file AnnocProc\&.java\fR:

   692 .sp     

   693 .nf     

   694 \f3import java\&.util\&.*;\fP

   695 .fi     

   696 .nf     

   697 \f3import javax\&.annotation\&.processing\&.*;\fP

   698 .fi     

   699 .nf     

   700 \f3import javax\&.lang\&.model\&.*;\fP

   701 .fi     

   702 .nf     

   703 \f3import\&.javaz\&.lang\&.model\&.element\&.*;\fP

   704 .fi     

   705 .nf     

   706 \f3\fP

   707 .fi     

   708 .nf     

   709 \f3@SupportedAnnotationTypes("NotAnno")\fP

   710 .fi     

   711 .nf     

   712 \f3public class AnnoProc extends AbstractProcessor {\fP

   713 .fi     

   714 .nf     

   715 \f3  public boolean process(Set<? extends TypeElement> elems, RoundEnvironment renv){\fP

   716 .fi     

   717 .nf     

   718 \f3     return true;\fP

   719 .fi     

   720 .nf     

   721 \f3  }\fP

   722 .fi     

   723 .nf     

   724 \f3\fP

   725 .fi     

   726 .nf     

   727 \f3  public SourceVersion getSupportedSourceVersion() {\fP

   728 .fi     

   729 .nf     

   730 \f3     return SourceVersion\&.latest();\fP

   731 .fi     

   732 .nf     

   733 \f3   }\fP

   734 .fi     

   735 .nf     

   736 \f3}\fP

   737 .fi     

   738 .nf     

   739 \f3\fP

   740 .fi     

   741 .sp     

   742 

   743 

   744 \fISource file AnnosWithoutProcessors\&.java\fR:

   745 .sp     

   746 .nf     

   747 \f3@interface Anno { }\fP

   748 .fi     

   749 .nf     

   750 \f3\fP

   751 .fi     

   752 .nf     

   753 \f3@Anno\fP

   754 .fi     

   755 .nf     

   756 \f3class AnnosWithoutProcessors { }\fP

   757 .fi     

   758 .nf     

   759 \f3\fP

   760 .fi     

   761 .sp     

   762 

   763 

   764 The following commands compile the annotation processor \f3AnnoProc\fR, then run this annotation processor against the source file \f3AnnosWithoutProcessors\&.java\fR:

   765 .sp     

   766 .nf     

   767 \f3javac AnnoProc\&.java\fP

   768 .fi     

   769 .nf     

   770 \f3javac \-cp \&. \-Xlint:processing \-processor AnnoProc \-proc:only AnnosWithoutProcessors\&.java\fP

   771 .fi     

   772 .nf     

   773 \f3\fP

   774 .fi     

   775 .sp     

   776 

   777 

   778 When the compiler runs the annotation processor against the source file \f3AnnosWithoutProcessors\&.java\fR, it generates the following warning:

   779 .sp     

   780 .nf     

   781 \f3warning: [processing] No processor claimed any of these annotations: Anno\fP

   782 .fi     

   783 .nf     

   784 \f3\fP

   785 .fi     

   786 .sp     

   787 

   788 

   789 To resolve this issue, you can rename the annotation defined and used in the class \f3AnnosWithoutProcessors\fR from \f3Anno\fR to \f3NotAnno\fR\&.

   790 .TP     

   791 rawtypes

   792 Warns about unchecked operations on raw types\&. The following statement generates a \f3rawtypes\fR warning:

   793 .sp     

   794 .nf     

   795 \f3void countElements(List l) { \&.\&.\&. }\fP

   796 .fi     

   797 .nf     

   798 \f3\fP

   799 .fi     

   800 .sp     

   801 

   802 

   803 The following example does not generate a \f3rawtypes\fR warning

   804 .sp     

   805 .nf     

   806 \f3void countElements(List<?> l) { \&.\&.\&. }\fP

   807 .fi     

   808 .nf     

   809 \f3\fP

   810 .fi     

   811 .sp     

   812 

   813 

   814 \f3List\fR is a raw type\&. However, \f3List<?>\fR is an unbounded wildcard parameterized type\&. Because \f3List\fR is a parameterized interface, always specify its type argument\&. In this example, the \f3List\fR formal argument is specified with an unbounded wildcard (\f3?\fR) as its formal type parameter, which means that the \f3countElements\fR method can accept any instantiation of the \f3List\fR interface\&.

   815 .TP     

   816 Serial

   817 Warns about missing \f3serialVersionUID\fR definitions on serializable classes, for example:

   818 .sp     

   819 .nf     

   820 \f3public class PersistentTime implements Serializable\fP

   821 .fi     

   822 .nf     

   823 \f3{\fP

   824 .fi     

   825 .nf     

   826 \f3  private Date time;\fP

   827 .fi     

   828 .nf     

   829 \f3\fP

   830 .fi     

   831 .nf     

   832 \f3   public PersistentTime() {\fP

   833 .fi     

   834 .nf     

   835 \f3     time = Calendar\&.getInstance()\&.getTime();\fP

   836 .fi     

   837 .nf     

   838 \f3   }\fP

   839 .fi     

   840 .nf     

   841 \f3\fP

   842 .fi     

   843 .nf     

   844 \f3   public Date getTime() {\fP

   845 .fi     

   846 .nf     

   847 \f3     return time;\fP

   848 .fi     

   849 .nf     

   850 \f3   }\fP

   851 .fi     

   852 .nf     

   853 \f3}\fP

   854 .fi     

   855 .nf     

   856 \f3\fP

   857 .fi     

   858 .sp     

   859 

   860 

   861 The compiler generates the following warning:

   862 .sp     

   863 .nf     

   864 \f3warning: [serial] serializable class PersistentTime has no definition of\fP

   865 .fi     

   866 .nf     

   867 \f3serialVersionUID\fP

   868 .fi     

   869 .nf     

   870 \f3\fP

   871 .fi     

   872 .sp     

   873 

   874 

   875 If a serializable class does not explicitly declare a field named \f3serialVersionUID\fR, then the serialization runtime environment calculates a default \f3serialVersionUID\fR value for that class based on various aspects of the class, as described in the Java Object Serialization Specification\&. However, it is strongly recommended that all serializable classes explicitly declare \f3serialVersionUID\fR values because the default process of computing \f3serialVersionUID\fR vales is highly sensitive to class details that can vary depending on compiler implementations, and as a result, might cause an unexpected \f3InvalidClassExceptions\fR during deserialization\&. To guarantee a consistent \f3serialVersionUID\fR value across different Java compiler implementations, a serializable class must declare an explicit \f3serialVersionUID\fR value\&.

   876 .TP     

   877 static

   878 Warns about issues relating to the use of statics, for example:

   879 .sp     

   880 .nf     

   881 \f3class XLintStatic {\fP

   882 .fi     

   883 .nf     

   884 \f3    static void m1() { }\fP

   885 .fi     

   886 .nf     

   887 \f3    void m2() { this\&.m1(); }\fP

   888 .fi     

   889 .nf     

   890 \f3}\fP

   891 .fi     

   892 .nf     

   893 \f3\fP

   894 .fi     

   895 .sp     

   896 

   897 

   898 The compiler generates the following warning:

   899 .sp     

   900 .nf     

   901 \f3warning: [static] static method should be qualified by type name, \fP

   902 .fi     

   903 .nf     

   904 \f3XLintStatic, instead of by an expression\fP

   905 .fi     

   906 .nf     

   907 \f3\fP

   908 .fi     

   909 .sp     

   910 

   911 

   912 To resolve this issue, you can call the \f3static\fR method \f3m1\fR as follows:

   913 .sp     

   914 .nf     

   915 \f3XLintStatic\&.m1();\fP

   916 .fi     

   917 .nf     

   918 \f3\fP

   919 .fi     

   920 .sp     

   921 

   922 

   923 Alternately, you can remove the \f3static\fR keyword from the declaration of the method \f3m1\fR\&.

   924 .TP     

   925 try

   926 Warns about issues relating to use of \f3try\fR blocks, including try-with-resources statements\&. For example, a warning is generated for the following statement because the resource \f3ac\fR declared in the \f3try\fR block is not used:

   927 .sp     

   928 .nf     

   929 \f3try ( AutoCloseable ac = getResource() ) {    // do nothing}\fP

   930 .fi     

   931 .nf     

   932 \f3\fP

   933 .fi     

   934 .sp     

   935 

   936 .TP     

   937 unchecked

   938 Gives more detail for unchecked conversion warnings that are mandated by the Java Language Specification, for example:

   939 .sp     

   940 .nf     

   941 \f3List l = new ArrayList<Number>();\fP

   942 .fi     

   943 .nf     

   944 \f3List<String> ls = l;       // unchecked warning\fP

   945 .fi     

   946 .nf     

   947 \f3\fP

   948 .fi     

   949 .sp     

   950 

   951 

   952 During type erasure, the types \f3ArrayList<Number>\fR and \f3List<String>\fR become \f3ArrayList\fR and \f3List\fR, respectively\&.

   953 

   954 The \f3ls\fR command has the parameterized type \f3List<String>\fR\&. When the \f3List\fR referenced by \f3l\fR is assigned to \f3ls\fR, the compiler generates an unchecked warning\&. At compile time, the compiler and JVM cannot determine whether \f3l\fR refers to a \f3List<String>\fR type\&. In this case, \f3l\fR does not refer to a \f3List<String>\fR type\&. As a result, heap pollution occurs\&.

   955 

   956 A heap pollution situation occurs when the \f3List\fR object \f3l\fR, whose static type is \f3List<Number>\fR, is assigned to another \f3List\fR object, \f3ls\fR, that has a different static type, \f3List<String>\fR\&. However, the compiler still allows this assignment\&. It must allow this assignment to preserve backward compatibility with releases of Java SE that do not support generics\&. Because of type erasure, \f3List<Number>\fR and \f3List<String>\fR both become \f3List\fR\&. Consequently, the compiler allows the assignment of the object \f3l\fR\f3,\fR which has a raw type of \f3List\fR, to the object \f3ls\fR\&.

   957 .TP     

   958 varargs

   959 Warns about unsafe usages of variable arguments (\f3varargs\fR) methods, in particular, those that contain non-reifiable arguments, for example:

   960 .sp     

   961 .nf     

   962 \f3public class ArrayBuilder {\fP

   963 .fi     

   964 .nf     

   965 \f3  public static <T> void addToList (List<T> listArg, T\&.\&.\&. elements) {\fP

   966 .fi     

   967 .nf     

   968 \f3    for (T x : elements) {\fP

   969 .fi     

   970 .nf     

   971 \f3      listArg\&.add(x);\fP

   972 .fi     

   973 .nf     

   974 \f3    }\fP

   975 .fi     

   976 .nf     

   977 \f3  }\fP

   978 .fi     

   979 .nf     

   980 \f3}\fP

   981 .fi     

   982 .nf     

   983 \f3\fP

   984 .fi     

   985 .sp     

   986 

   987 

   988 \fINote:\fR A non-reifiable type is a type whose type information is not fully available at runtime\&.

   989 

   990 The compiler generates the following warning for the definition of the method \f3ArrayBuilder\&.addToList\fR

   991 .sp     

   992 .nf     

   993 \f3warning: [varargs] Possible heap pollution from parameterized vararg type T\fP

   994 .fi     

   995 .nf     

   996 \f3\fP

   997 .fi     

   998 .sp     

   999 

  1000 

  1001 When the compiler encounters a varargs method, it translates the \f3varargs\fR formal parameter into an array\&. However, the Java programming language does not permit the creation of arrays of parameterized types\&. In the method \f3ArrayBuilder\&.addToList\fR, the compiler translates the \f3varargs\fR formal parameter \f3T\&.\&.\&.\fR elements to the formal parameter \f3T[]\fR elements, an array\&. However, because of type erasure, the compiler converts the \f3varargs\fR formal parameter to \f3Object[]\fR elements\&. Consequently, there is a possibility of heap pollution\&.

  1002 .SH COMMAND-LINE\ ARGUMENT\ FILES    

  1003 To shorten or simplify the \f3javac\fR command, you can specify one or more files that contain arguments to the \f3javac\fR command (except \f3-J\fR options)\&. This enables you to create \f3javac\fR commands of any length on any operating system\&.

  1004 .PP

  1005 An argument file can include \f3javac\fR options and source file names in any combination\&. The arguments within a file can be separated by spaces or new line characters\&. If a file name contains embedded spaces, then put the whole file name in double quotation marks\&.

  1006 .PP

  1007 File Names within an argument file are relative to the current directory, not the location of the argument file\&. Wild cards (*) are not allowed in these lists (such as for specifying \f3*\&.java\fR)\&. Use of the at sign (@) to recursively interpret files is not supported\&. The \f3-J\fR options are not supported because they are passed to the launcher, which does not support argument files\&.

  1008 .PP

  1009 When executing the \f3javac\fR command, pass in the path and name of each argument file with the at sign (@) leading character\&. When the \f3javac\fR command encounters an argument beginning with the at sign (@), it expands the contents of that file into the argument list\&.

  1010 .PP

  1011 \f3Example 1 Single Argument File\fR

  1012 .PP

  1013 You could use a single argument file named \f3argfile\fR to hold all \f3javac\fR arguments:

  1014 .sp     

  1015 .nf     

  1016 \f3javac @argfile\fP

  1017 .fi     

  1018 .nf     

  1019 \f3\fP

  1020 .fi     

  1021 .sp     

  1022 This argument file could contain the contents of both files shown in Example 2

  1023 .PP

  1024 \f3Example 2 Two Argument Files\fR

  1025 .PP

  1026 You can create two argument files: one for the \f3javac\fR options and the other for the source file names\&. Note that the following lists have no line-continuation characters\&.

  1027 .PP

  1028 Create a file named options that contains the following:

  1029 .sp     

  1030 .nf     

  1031 \f3\-d classes\fP

  1032 .fi     

  1033 .nf     

  1034 \f3\-g\fP

  1035 .fi     

  1036 .nf     

  1037 \f3\-sourcepath /java/pubs/ws/1\&.3/src/share/classes\fP

  1038 .fi     

  1039 .nf     

  1040 \f3\fP

  1041 .fi     

  1042 .sp     

  1043 Create a file named classes that contains the following:

  1044 .sp     

  1045 .nf     

  1046 \f3MyClass1\&.java\fP

  1047 .fi     

  1048 .nf     

  1049 \f3MyClass2\&.java\fP

  1050 .fi     

  1051 .nf     

  1052 \f3MyClass3\&.java\fP

  1053 .fi     

  1054 .nf     

  1055 \f3\fP

  1056 .fi     

  1057 .sp     

  1058 Then, run the \f3javac\fR command as follows:

  1059 .sp     

  1060 .nf     

  1061 \f3javac @options @classes\fP

  1062 .fi     

  1063 .nf     

  1064 \f3\fP

  1065 .fi     

  1066 .sp     

  1067 \f3Example 3 Argument Files with Paths\fR

  1068 .PP

  1069 The argument files can have paths, but any file names inside the files are relative to the current working directory (not \f3path1\fR or \f3path2\fR):

  1070 .sp     

  1071 .nf     

  1072 \f3javac @path1/options @path2/classes\fP

  1073 .fi     

  1074 .nf     

  1075 \f3\fP

  1076 .fi     

  1077 .sp     

  1078 .SH ANNOTATION\ PROCESSING    

  1079 The \f3javac\fR command provides direct support for annotation processing, superseding the need for the separate annotation processing command, \f3apt\fR\&.

  1080 .PP

  1081 The API for annotation processors is defined in the \f3javax\&.annotation\&.processing\fR and j\f3avax\&.lang\&.model\fR packages and subpackages\&.

  1082 .SS HOW\ ANNOTATION\ PROCESSING\ WORKS    

  1083 Unless annotation processing is disabled with the \f3-proc:none\fR option, the compiler searches for any annotation processors that are available\&. The search path can be specified with the \f3-processorpath\fR option\&. If no path is specified, then the user class path is used\&. Processors are located by means of service provider-configuration files named \f3META-INF/services/javax\&.annotation\&.processing\fR\&.Processor on the search path\&. Such files should contain the names of any annotation processors to be used, listed one per line\&. Alternatively, processors can be specified explicitly, using the \f3-processor\fR option\&.

  1084 .PP

  1085 After scanning the source files and classes on the command line to determine what annotations are present, the compiler queries the processors to determine what annotations they process\&. When a match is found, the processor is called\&. A processor can claim the annotations it processes, in which case no further attempt is made to find any processors for those annotations\&. After all of the annotations are claimed, the compiler does not search for additional processors\&.

  1086 .PP

  1087 If any processors generate new source files, then another round of annotation processing occurs: Any newly generated source files are scanned, and the annotations processed as before\&. Any processors called on previous rounds are also called on all subsequent rounds\&. This continues until no new source files are generated\&.

  1088 .PP

  1089 After a round occurs where no new source files are generated, the annotation processors are called one last time, to give them a chance to complete any remaining work\&. Finally, unless the \f3-proc:only\fR option is used, the compiler compiles the original and all generated source files\&.

  1090 .SS IMPLICITLY\ LOADED\ SOURCE\ FILES    

  1091 To compile a set of source files, the compiler might need to implicitly load additional source files\&. See Searching for Types\&. Such files are currently not subject to annotation processing\&. By default, the compiler gives a warning when annotation processing occurred and any implicitly loaded source files are compiled\&. The \f3-implicit\fR option provides a way to suppress the warning\&.

  1092 .SH SEARCHING\ FOR\ TYPES    

  1093 To compile a source file, the compiler often needs information about a type, but the type definition is not in the source files specified on the command line\&. The compiler needs type information for every class or interface used, extended, or implemented in the source file\&. This includes classes and interfaces not explicitly mentioned in the source file, but that provide information through inheritance\&.

  1094 .PP

  1095 For example, when you create a subclass \f3java\&.applet\&.Applet\fR, you are also using the ancestor classes of \f3Applet\fR: \f3java\&.awt\&.Panel\fR, \f3java\&.awt\&.Container\fR, \f3java\&.awt\&.Component\fR, and \f3java\&.lang\&.Object\fR\&.

  1096 .PP

  1097 When the compiler needs type information, it searches for a source file or class file that defines the type\&. The compiler searches for class files first in the bootstrap and extension classes, then in the user class path (which by default is the current directory)\&. The user class path is defined by setting the \f3CLASSPATH\fR environment variable or by using the \f3-classpath\fR option\&.

  1098 .PP

  1099 If you set the \f3-sourcepath\fR option, then the compiler searches the indicated path for source files\&. Otherwise, the compiler searches the user class path for both class files and source files\&.

  1100 .PP

  1101 You can specify different bootstrap or extension classes with the \f3-bootclasspath\fR and the \f3-extdirs\fR options\&. See Cross-Compilation Options\&.

  1102 .PP

  1103 A successful type search may produce a class file, a source file, or both\&. If both are found, then you can use the \f3-Xprefer\fR option to instruct the compiler which to use\&. If \f3newer\fR is specified, then the compiler uses the newer of the two files\&. If \f3source\fR is specified, the compiler uses the source file\&. The default is \f3newer\fR\&.

  1104 .PP

  1105 If a type search finds a source file for a required type, either by itself, or as a result of the setting for the \f3-Xprefer\fR option, then the compiler reads the source file to get the information it needs\&. By default the compiler also compiles the source file\&. You can use the \f3-implicit\fR option to specify the behavior\&. If \f3none\fR is specified, then no class files are generated for the source file\&. If \f3class\fR is specified, then class files are generated for the source file\&.

  1106 .PP

  1107 The compiler might not discover the need for some type information until after annotation processing completes\&. When the type information is found in a source file and no \f3-implicit\fR option is specified, the compiler gives a warning that the file is being compiled without being subject to annotation processing\&. To disable the warning, either specify the file on the command line (so that it will be subject to annotation processing) or use the \f3-implicit\fR option to specify whether or not class files should be generated for such source files\&.

  1108 .SH PROGRAMMATIC\ INTERFACE    

  1109 The \f3javac\fR command supports the new Java Compiler API defined by the classes and interfaces in the \f3javax\&.tools\fR package\&.

  1110 .SS EXAMPLE    

  1111 To compile as though providing command-line arguments, use the following syntax:

  1112 .sp     

  1113 .nf     

  1114 \f3JavaCompiler javac = ToolProvider\&.getSystemJavaCompiler();\fP

  1115 .fi     

  1116 .nf     

  1117 \f3JavaCompiler javac = ToolProvider\&.getSystemJavaCompiler();\fP

  1118 .fi     

  1119 .nf     

  1120 \f3\fP

  1121 .fi     

  1122 .sp     

  1123 The example writes diagnostics to the standard output stream and returns the exit code that \f3javac\fR would give when called from the command line\&.

  1124 .PP

  1125 You can use other methods in the \f3javax\&.tools\&.JavaCompiler\fR interface to handle diagnostics, control where files are read from and written to, and more\&.

  1126 .SS OLD\ INTERFACE    

  1127 \fINote:\fR This API is retained for backward compatibility only\&. All new code should use the newer Java Compiler API\&.

  1128 .PP

  1129 The \f3com\&.sun\&.tools\&.javac\&.Main\fR class provides two static methods to call the compiler from a program:

  1130 .sp     

  1131 .nf     

  1132 \f3public static int compile(String[] args);\fP

  1133 .fi     

  1134 .nf