TestDescription.java

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/*
 * @test
 * @key stress randomness
 *
 * @summary converted from VM Testbase gc/gctests/LargeObjects/large004.
 * VM Testbase keywords: [gc, stress, stressopt, nonconcurrent]
 * VM Testbase readme:
 * DESCRIPTION
 *     The test checks that Garbage Collector correctly does not throw any
 *     unexpected exceptions/errors while allocating large objects (classes
 *     that have more than 65535 fields and classes that have less than 65535
 *     fields). 65535 of fields is a limitation for JVM (see JVM specification
 *     Second edition 4.10).
 *     Since it is impossible to create one class with about 65535 of fields
 *     (javac cannot compile it), a child class extends a parent class, so the
 *     fields are devided into two subsets. However, the child class still has
 *     about 65535 of fields.
 *     The test starts a number of threads. This number is either set in *.cfg
 *     file or is calculated by the test itself based on the machine (see
 *     nsk.share.gc.Algorithms.getThreadsCount() method). As soon as all threads
 *     are started, each thread begins its checking.
 *     There are 13 classes to be loaded by each thread. These classes are
 *     generated by nsk.share.gc.Generator (see its javadoc for more details).
 *     Each class has a huge number of fields, but this number is less than the JVM
 *     limitation.
 *     The test loads the classes with nsk.share.gc.GCClassUnloader class that
 *     extends nsk.share.ClassUnloader and has a bit different algorith of eating
 *     heap. As soon as a class is loaded, the test creates an instance of
 *     it - allocates an object of that type. Then it drops references to the
 *     class and to the instance and tries to unload the class. The test does not
 *     expect any exceptions to be thrown.
 *     Additionaly to original tests this test create object with large count of
 *     field which contains also a reference to other such object wich also
 *     contains same reference and so on. The deep of such aggregation is controlled
 *     by the test. These references are verified after GC.
 *
 * @library /vmTestbase
 *          /test/lib
 *
 * @comment generate and compile nsk.share.gc.newclass.* classes
 * @run driver nsk.share.gc.GenClassesBuilder
 *
 * @run main/othervm
 *      -XX:-UseGCOverheadLimit
 *      gc.gctests.LargeObjects.large001.large001
 *      -largeClassesPath classes
 *      -isOverLimitFields true
 *      -aggregationDepth 1
 *      -t 1
 */