--- a/hotspot/test/gc/arguments/TestDynMaxHeapFreeRatio.java	Tue May 20 10:04:03 2014 -0700
+++ b/hotspot/test/gc/arguments/TestDynMaxHeapFreeRatio.java	Tue May 20 18:25:14 2014 +0400
@@ -21,6 +21,11 @@
  * questions.
  */
 
+import static com.oracle.java.testlibrary.Asserts.assertEQ;
+import static com.oracle.java.testlibrary.Asserts.assertFalse;
+import static com.oracle.java.testlibrary.Asserts.assertTrue;
+import com.oracle.java.testlibrary.DynamicVMOption;
+
 /**
  * @test TestDynMaxHeapFreeRatio
  * @bug 8028391
@@ -33,32 +38,45 @@
  * @run main/othervm -XX:MinHeapFreeRatio=51 -XX:MaxHeapFreeRatio=52 TestDynMaxHeapFreeRatio
  * @run main/othervm -XX:MinHeapFreeRatio=75 -XX:MaxHeapFreeRatio=100 TestDynMaxHeapFreeRatio
  */
-import com.oracle.java.testlibrary.TestDynamicVMOption;
-import com.oracle.java.testlibrary.DynamicVMOptionChecker;
-
-public class TestDynMaxHeapFreeRatio extends TestDynamicVMOption {
-
-    public static final String MinFreeRatioFlagName = "MinHeapFreeRatio";
-    public static final String MaxFreeRatioFlagName = "MaxHeapFreeRatio";
-
-    public TestDynMaxHeapFreeRatio() {
-        super(MaxFreeRatioFlagName);
-    }
-
-    public void test() {
-
-        int minHeapFreeValue = DynamicVMOptionChecker.getIntValue(MinFreeRatioFlagName);
-        System.out.println(MinFreeRatioFlagName + " = " + minHeapFreeValue);
-
-        testPercentageValues();
-
-        checkInvalidValue(Integer.toString(minHeapFreeValue - 1));
-        checkValidValue(Integer.toString(minHeapFreeValue));
-        checkValidValue("100");
-    }
+public class TestDynMaxHeapFreeRatio {
 
     public static void main(String args[]) throws Exception {
-        new TestDynMaxHeapFreeRatio().test();
+
+        // low boundary value
+        int minValue = DynamicVMOption.getInt("MinHeapFreeRatio");
+        System.out.println("MinHeapFreeRatio= " + minValue);
+
+        String badValues[] = {
+            null,
+            "",
+            "not a number",
+            "8.5", "-0.01",
+            Integer.toString(Integer.MIN_VALUE),
+            Integer.toString(Integer.MAX_VALUE),
+            Integer.toString(minValue - 1),
+            "-1024", "-1", "101", "1997"
+        };
+
+        String goodValues[] = {
+            Integer.toString(minValue),
+            Integer.toString(minValue + 1),
+            Integer.toString((minValue + 100) / 2),
+            "99", "100"
+        };
+
+        DynamicVMOption option = new DynamicVMOption("MaxHeapFreeRatio");
+
+        assertTrue(option.isWriteable(), "Option " + option.name
+                + " is expected to be writable");
+
+        for (String v : badValues) {
+            assertFalse(option.isValidValue(v),
+                    "'" + v + "' is expected to be illegal for flag " + option.name);
+        }
+        for (String v : goodValues) {
+            option.setValue(v);
+            String newValue = option.getValue();
+            assertEQ(v, newValue);
+        }
     }
-
 }

--- a/hotspot/test/gc/arguments/TestDynMinHeapFreeRatio.java	Tue May 20 10:04:03 2014 -0700
+++ b/hotspot/test/gc/arguments/TestDynMinHeapFreeRatio.java	Tue May 20 18:25:14 2014 +0400
@@ -33,30 +33,52 @@
  * @run main/othervm -XX:MinHeapFreeRatio=51 -XX:MaxHeapFreeRatio=52 TestDynMinHeapFreeRatio
  * @run main/othervm -XX:MinHeapFreeRatio=75 -XX:MaxHeapFreeRatio=100 TestDynMinHeapFreeRatio
  */
-import com.oracle.java.testlibrary.TestDynamicVMOption;
-import com.oracle.java.testlibrary.DynamicVMOptionChecker;
-
-public class TestDynMinHeapFreeRatio extends TestDynamicVMOption {
-
-    public static final String MinFreeRatioFlagName = "MinHeapFreeRatio";
-    public static final String MaxFreeRatioFlagName = "MaxHeapFreeRatio";
+import static com.oracle.java.testlibrary.Asserts.assertEQ;
+import static com.oracle.java.testlibrary.Asserts.assertFalse;
+import static com.oracle.java.testlibrary.Asserts.assertTrue;
+import com.oracle.java.testlibrary.DynamicVMOption;
 
-    public TestDynMinHeapFreeRatio() {
-        super(MinFreeRatioFlagName);
-    }
-
-    public void test() {
-        int maxHeapFreeValue = DynamicVMOptionChecker.getIntValue(MaxFreeRatioFlagName);
-        System.out.println(MaxFreeRatioFlagName + " = " + maxHeapFreeValue);
-
-        testPercentageValues();
-
-        checkInvalidValue(Integer.toString(maxHeapFreeValue + 1));
-        checkValidValue(Integer.toString(maxHeapFreeValue));
-        checkValidValue("0");
-    }
+public class TestDynMinHeapFreeRatio {
 
     public static void main(String args[]) throws Exception {
-        new TestDynMinHeapFreeRatio().test();
+
+        // high boundary value
+        int maxValue = DynamicVMOption.getInt("MaxHeapFreeRatio");
+        System.out.println("MaxHeapFreeRatio= " + maxValue);
+
+        String badValues[] = {
+            null,
+            "",
+            "not a number",
+            "8.5", "-0.01",
+            Integer.toString(Integer.MIN_VALUE),
+            Integer.toString(Integer.MAX_VALUE),
+            Integer.toString(maxValue + 1),
+            "-1024", "-1", "101", "1997"
+        };
+
+        String goodValues[] = {
+            Integer.toString(maxValue),
+            Integer.toString(maxValue - 1),
+            Integer.toString(maxValue / 2),
+            "0", "1"
+        };
+
+        // option under test
+        DynamicVMOption option = new DynamicVMOption("MinHeapFreeRatio");
+
+        assertTrue(option.isWriteable(), "Option " + option.name
+                + " is expected to be writable");
+
+        for (String v : badValues) {
+            assertFalse(option.isValidValue(v),
+                    "'" + v + "' is expected to be illegal for flag " + option.name);
+        }
+
+        for (String v : goodValues) {
+            option.setValue(v);
+            String newValue = option.getValue();
+            assertEQ(v, newValue);
+        }
     }
 }

--- a/hotspot/test/gc/parallelScavenge/TestDynShrinkHeap.java	Tue May 20 10:04:03 2014 -0700
+++ b/hotspot/test/gc/parallelScavenge/TestDynShrinkHeap.java	Tue May 20 18:25:14 2014 +0400
@@ -28,8 +28,7 @@
  * @library /testlibrary
  * @run main/othervm -XX:+UseAdaptiveSizePolicyWithSystemGC -XX:+UseParallelGC -XX:MinHeapFreeRatio=0 -XX:MaxHeapFreeRatio=100 -verbose:gc TestDynShrinkHeap
  */
-
-import com.oracle.java.testlibrary.TestDynamicVMOption;
+import com.oracle.java.testlibrary.DynamicVMOption;
 import java.lang.management.ManagementFactory;
 import java.lang.management.MemoryUsage;
 import java.util.ArrayList;
@@ -44,12 +43,7 @@
     private static ArrayList<byte[]> list = new ArrayList<>(0);
     private static final int M = 1024 * 1024; // to make heap more manageable by test code
 
-    private final TestDynamicVMOption maxRatioOption;
-    private final TestDynamicVMOption minRatioOption;
-
     public TestDynShrinkHeap() {
-        minRatioOption = new TestDynamicVMOption(MIN_FREE_RATIO_FLAG_NAME);
-        maxRatioOption = new TestDynamicVMOption(MAX_FREE_RATIO_FLAG_NAME);
     }
 
     private final void test() {
@@ -86,7 +80,8 @@
     }
 
     private void free() {
-        maxRatioOption.setIntValue(minRatioOption.getIntValue() + 1);
+        int min = DynamicVMOption.getInt(MIN_FREE_RATIO_FLAG_NAME);
+        DynamicVMOption.setInt(MAX_FREE_RATIO_FLAG_NAME, min);
         System.gc();
         MemoryUsagePrinter.printMemoryUsage("under pressure");
     }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/testlibrary/com/oracle/java/testlibrary/DynamicVMOption.java	Tue May 20 18:25:14 2014 +0400
@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) 2014, 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.
+ */
+package com.oracle.java.testlibrary;
+
+import com.sun.management.HotSpotDiagnosticMXBean;
+import java.lang.management.ManagementFactory;
+
+/**
+ * A utility class to work with VM options which could be altered during
+ * execution.
+ *
+ * This class is a wrapper around {@code com.sun.management.VMOption}.
+ * It provides more convenient interface to read/write the values.
+ *
+ */
+public class DynamicVMOption {
+
+    private final HotSpotDiagnosticMXBean mxBean;
+
+    /**
+     * VM option name, like "MinHeapFreeRatio".
+     */
+    public final String name;
+
+    /**
+     * Creates an instance of DynamicVMOption.
+     *
+     * @param name the VM option name
+     */
+    public DynamicVMOption(String name) {
+        this.name = name;
+        mxBean = ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class);
+    }
+
+    /**
+     * Sets a new value for the option.
+     * Trying to set not applicable value will cause IllegalArgumentException.
+     * Behavior with null is undefined, most likely NPE will be thrown.
+     *
+     * @param newValue the value to be set
+     * @see #getValue()
+     * @throws IllegalArgumentException if newValue is not applicable to the option
+     */
+    public final void setValue(String newValue) {
+        mxBean.setVMOption(name, newValue);
+    }
+
+    /**
+     * Returns the value of option.
+     *
+     * @return the current option value
+     * @see #setValue(java.lang.String)
+     */
+    public final String getValue() {
+        return mxBean.getVMOption(name).getValue();
+    }
+
+    /**
+     * Returns true, if option is writable, false otherwise.
+     *
+     * @return true, if option is writable, false otherwise
+     */
+    public final boolean isWriteable() {
+        return mxBean.getVMOption(name).isWriteable();
+    }
+
+    /**
+     * Checks if the given value is applicable for the option.
+     *
+     * This method tries to set the option to the new value. If no exception
+     * has been thrown the value is treated as valid.
+     *
+     * Calling this method will not change the option value. After an attempt
+     * to set a new value, the option will be restored to its previous value.
+     *
+     * @param value the value to verify
+     * @return true if option could be set to the given value
+     */
+    public boolean isValidValue(String value) {
+        boolean isValid = true;
+        String oldValue = getValue();
+        try {
+            setValue(value);
+        } catch (NullPointerException e) {
+            if (value == null) {
+                isValid = false;
+            }
+        } catch (IllegalArgumentException e) {
+            isValid = false;
+        } finally {
+            setValue(oldValue);
+        }
+        return isValid;
+    }
+
+    /**
+     * Returns the value of the given VM option as String.
+     *
+     * This is a simple shortcut for {@code new DynamicVMOption(name).getValue()}
+     *
+     * @param name the name of VM option
+     * @return value as a string
+     * @see #getValue()
+     */
+    public static String getString(String name) {
+        return new DynamicVMOption(name).getValue();
+    }
+
+    /**
+     * Returns the value of the given option as int.
+     *
+     * @param name the name of VM option
+     * @return value parsed as integer
+     * @see #getString(java.lang.String)
+     *
+     */
+    public static int getInt(String name) {
+        return Integer.parseInt(getString(name));
+    }
+
+    /**
+     * Sets the VM option to a new value.
+     *
+     * This is a simple shortcut for {@code new DynamicVMOption(name).setValue(value)}
+     *
+     * @param name the name of VM option
+     * @param value the value to be set
+     * @see #setValue(java.lang.String)
+     */
+    public static void setString(String name, String value) {
+        new DynamicVMOption(name).setValue(value);
+    }
+
+    /**
+     * Sets the VM option value to a new integer value.
+     *
+     * @param name the name of VM option
+     * @param value the integer value to be set
+     * @see #setString(java.lang.String, java.lang.String)
+     */
+    public static void setInt(String name, int value) {
+        new DynamicVMOption(name).setValue(Integer.toString(value));
+    }
+
+}

--- a/hotspot/test/testlibrary/com/oracle/java/testlibrary/DynamicVMOptionChecker.java	Tue May 20 10:04:03 2014 -0700
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,121 +0,0 @@
-/*
- * Copyright (c) 2014, 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.
- */
-package com.oracle.java.testlibrary;
-
-import com.sun.management.HotSpotDiagnosticMXBean;
-import com.sun.management.VMOption;
-import java.lang.management.ManagementFactory;
-
-/**
- * Simple class to check writeability, invalid and valid values for VMOption
- */
-public class DynamicVMOptionChecker {
-
-    /**
-     * Reads VM option from PlatformMXBean and parse it to integer value
-     *
-     * @param name of option
-     * @return parsed value
-     */
-    public static int getIntValue(String name) {
-
-        VMOption option = ManagementFactory.
-                getPlatformMXBean(HotSpotDiagnosticMXBean.class).
-                getVMOption(name);
-
-        return Integer.parseInt(option.getValue());
-    }
-
-    /**
-     * Sets VM option value
-     *
-     * @param name of option
-     * @param value to set
-     */
-    public static void setIntValue(String name, int value) {
-        ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class).setVMOption(name, Integer.toString(value));
-    }
-
-    /**
-     * Checks that VM option is dynamically writable
-     *
-     * @param name
-     * @throws RuntimeException if option if not writable
-     * @return always true
-     */
-    public static boolean checkIsWritable(String name) {
-        VMOption option = ManagementFactory.
-                getPlatformMXBean(HotSpotDiagnosticMXBean.class).
-                getVMOption(name);
-
-        if (!option.isWriteable()) {
-            throw new RuntimeException(name + " is not writable");
-        }
-
-        return true;
-    }
-
-    /**
-     * Checks that value cannot be set
-     *
-     * @param name of flag
-     * @param value string representation of value to set
-     * @throws RuntimeException on error - when expected exception hasn't been thrown
-     */
-    public static void checkInvalidValue(String name, String value) {
-        // should throw
-        try {
-            ManagementFactory.
-                    getPlatformMXBean(HotSpotDiagnosticMXBean.class).
-                    setVMOption(name, value);
-
-        } catch (IllegalArgumentException e) {
-            return;
-        }
-
-        throw new RuntimeException("Expected IllegalArgumentException was not thrown, " + name + "= " + value);
-    }
-
-    /**
-     * Checks that value can be set
-     *
-     * @param name of flag to set
-     * @param value string representation of value to set
-     * @throws RuntimeException on error - when value in VM is not equal to origin
-     */
-    public static void checkValidValue(String name, String value) {
-        ManagementFactory.
-                getPlatformMXBean(HotSpotDiagnosticMXBean.class).
-                setVMOption(name, value);
-
-        VMOption option = ManagementFactory.
-                getPlatformMXBean(HotSpotDiagnosticMXBean.class).
-                getVMOption(name);
-
-        if (!option.getValue().equals(value)) {
-            throw new RuntimeException("Actual value of " + name + " \"" + option.getValue()
-                    + "\" not equal origin \"" + value + "\"");
-        }
-    }
-
-}

--- a/hotspot/test/testlibrary/com/oracle/java/testlibrary/TestDynamicVMOption.java	Tue May 20 10:04:03 2014 -0700
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,104 +0,0 @@
-/*
- * Copyright (c) 2014, 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.
- */
-package com.oracle.java.testlibrary;
-
-/**
- * Simple class to check writeability, invalid and valid values for concrete VMOption
- */
-public class TestDynamicVMOption {
-
-    private final String name;
-    private final int value;
-
-    /**
-     * Constructor
-     *
-     * @param name of VM option to test
-     */
-    public TestDynamicVMOption(String name) {
-        this.name = name;
-        this.value = DynamicVMOptionChecker.getIntValue(name);
-        System.out.println(this.name + " = " + this.value);
-    }
-
-    /**
-     * Checks that this value can accept valid percentage values and cannot accept invalid percentage values
-     *
-     * @throws RuntimeException
-     */
-    public void testPercentageValues() {
-        checkInvalidValue(Integer.toString(Integer.MIN_VALUE));
-        checkInvalidValue(Integer.toString(Integer.MAX_VALUE));
-        checkInvalidValue("-10");
-        checkInvalidValue("190");
-    }
-
-    /**
-     * Reads VM option from PlatformMXBean and parse it to integer value
-     *
-     * @return value
-     */
-    public int getIntValue() {
-        return DynamicVMOptionChecker.getIntValue(this.name);
-    }
-
-    /**
-     * Sets VM option value
-     *
-     * @param value to set
-     */
-    public void setIntValue(int value) {
-        DynamicVMOptionChecker.setIntValue(this.name, value);
-    }
-
-    /**
-     * Checks that this VM option is dynamically writable
-     *
-     * @throws RuntimeException if option if not writable
-     * @return true
-     */
-    public boolean checkIsWritable() throws RuntimeException {
-        return DynamicVMOptionChecker.checkIsWritable(this.name);
-    }
-
-    /**
-     * Checks that value for this VM option cannot be set
-     *
-     * @param value to check
-     * @throws RuntimeException on error - when expected exception hasn't been thrown
-     */
-    public void checkInvalidValue(String value) {
-        DynamicVMOptionChecker.checkInvalidValue(this.name, value);
-    }
-
-    /**
-     * Checks that value for this VM option can be set
-     *
-     * @param value to check
-     * @throws RuntimeException on error - when value in VM is not equal to origin
-     */
-    public void checkValidValue(String value) {
-        DynamicVMOptionChecker.checkValidValue(this.name, value);
-    }
-
-}