--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/io/StreamTokenizer/ReadAhead.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+   @bug 4150737
+   @summary Ensure that StreamTokenizer does not read any further ahead
+            than is absolutely necessary
+ */
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.io.StreamTokenizer;
+import java.io.IOException;
+
+
+public class ReadAhead {
+
+
+    /* An InputStream subclass that cannot read past a given limit */
+    private static class LimitedInputStream extends InputStream {
+
+        private String input;
+        private int limit;      /* Do not allow input[limit] to be read */
+        private int next = 0;
+
+        public LimitedInputStream(String input, int limit) {
+            this.input = input;
+            this.limit = limit;
+        }
+
+        public int read() throws IOException {
+            if (next >= limit)
+                throw new IOException("Attempted to read too far in stream");
+            return input.charAt(next++);
+        }
+
+    }
+
+
+    /* A Reader subclass that cannot read past a given limit */
+    private static class LimitedReader extends Reader {
+
+        private String input;
+        private int limit;      /* Do not allow input[limit] to be read */
+        private int next = 0;
+
+        public LimitedReader(String input, int limit) {
+            this.input = input;
+            this.limit = limit;
+        }
+
+        public int read() throws IOException {
+            if (next >= limit)
+                throw new IOException("Attempted to read too far in stream");
+            return input.charAt(next++);
+        }
+
+        public int read(char[] b, int off, int len) throws IOException {
+            int top = off + len;
+            int i;
+            for (i = off; i < top; i++) {
+                int c = read();
+                if (c < 0) break;
+                b[i] = (char)c;
+            }
+            return i - off;
+        }
+
+        public void close() { }
+
+    }
+
+
+    /* Interface for objects that can create new StreamTokenizers
+       with a given limited input */
+    private static interface StreamTokenizerMaker {
+        public StreamTokenizer create(String input, int limit);
+    }
+
+    private static void fail(String why) throws Exception {
+        throw new Exception(why);
+    }
+
+    private static void test(StreamTokenizer st) throws Exception {
+        st.eolIsSignificant(true);
+        int tt = st.nextToken();
+        if (tt != StreamTokenizer.TT_WORD) fail("expected TT_WORD");
+        if (!st.sval.equals("foo")) fail("expected word token \"foo\"");
+        tt = st.nextToken();
+        if (tt != StreamTokenizer.TT_EOL) fail("expected TT_EOL");
+    }
+
+    private static void test(StreamTokenizerMaker stm) throws Exception {
+        test(stm.create("foo\nx", 4));
+        test(stm.create("foo\r\nx", 4));
+    }
+
+
+    public static void main(String[] args) throws Exception {
+
+        /* InputStream case */
+        test(new StreamTokenizerMaker() {
+            public StreamTokenizer create(String input, int limit) {
+                return new StreamTokenizer(new LimitedInputStream(input, limit));
+            }});
+
+        /* Reader case */
+        test(new StreamTokenizerMaker() {
+            public StreamTokenizer create(String input, int limit) {
+                return new StreamTokenizer(new LimitedReader(input, limit));
+            }});
+
+    }
+
+}