JVM Tutorials - Herong's Tutorial Examples

∟Garbage Collection Tests

∟1076/800/80MB Test on HotSpot Client 1.6

This section provides a tutorial example on running GCTest2.java on HotSpot Client JVM 1.6.0_45 with 1076MB memory limit and a 800MB base plus 80MB fluctuating memory usage with object size of 1.25MB.

As a comparison, I ran GCTest2.java with the same parameters on HotSpot Client 1.6.0_45 my Windows 7 system: 

>\Progra~1\java\jrockit-jdk1.6.0_45-R28.2.7-4.1.0\bin\javac 
   GCTest2.java

\Progra~1\java\jdk1.6.0_45\bin\java -Xmx1076m GCTest2 1280 640 64
Test parameters:
   Object size: 1280KB
   Initial objects and data size: 640, 819200KB
   Added objects and data size: 64, 81920KB
Time    Total    Free    Used  Free  Total    Act.    Dead  Over
sec.     Mem.    Mem.    Mem.    %.   Obj.    Obj.    Obj.  Head
   1  1065152  163847  901305  15%  901120  819200   81920  185
   2  1065152   81926  983226   7%  983040  819200  163840  186
   3  1065152  163852  901300  15%  901120  819200   81920  180
   4  1065152   81931  983221   7%  983040  819200  163840  181
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        at GCTest2$MyObject.<init>(GCTest2.java:70)
        at GCTest2.myTest(GCTest2.java:37)

\Progra~1\java\jdk1.6.0_45\bin\java -Xmx1077m GCTest2 1280 640 64
Test parameters:
   Object size: 1280KB
   Initial objects and data size: 640, 819200KB
   Added objects and data size: 64, 81920KB
Time    Total    Free     Used  Free  Total    Act.    Dead    Over
sec.     Mem.    Mem.     Mem.    %.   Obj.    Obj.    Obj.    Head
   1  1067136  165831   901305  15%  901120  819200   81920     185
   2  1067136   83910   983226   7%  983040  819200  163840     186
   3  1067136    1985  1065151   0%  901120  819200   81920  164031
   5  1067136   83914   983222   7%  901120  819200   81920   82102
   6  1067136    1993  1065143   0%  983040  819200  163840   82103
   7  1067136    1993  1065143   0%  901120  819200   81920  164023
   9  1067136   83916   983220   7%  901120  819200   81920   82100
  10  1067136    1993  1065143   0%  983040  819200  163840   82103
  11  1067136    1995  1065141   0%  901120  819200   81920  164021
  12  1067136   83917   983219   7%  901120  819200   81920   82099
  13  1067136    1993  1065143   0%  983040  819200  163840   82103
  15  1067136    1994  1065142   0%  901120  819200   81920  164022
  16  1067136   83910   983226   7%  901120  819200   81920   82106
  17  1067136    1983  1065153   0%  983040  819200  163840   82113
  19  1067136    1980  1065156   0%  901120  819200   81920  164036
  20  1067136   83917   983219   7%  901120  819200   81920   82099
  21  1067136    1952  1065184   0%  983040  819200  163840   82144
  22  1067136    1991  1065145   0%  901120  819200   81920  164025
  24  1067136   83917   983219   7%  901120  819200   81920   82099
  25  1067136    1949  1065187   0%  983040  819200  163840   82147
  26  1067136    1991  1065145   0%  901120  819200   81920  164025
  27  1067136   83917   983219   7%  901120  819200   81920   82099
  28  1067136    1949  1065187   0%  983040  819200  163840   82147
  30  1067136    1991  1065145   0%  902400  819200   83200  162745
  31  1067136   83917   983219   7%  902400  819200   83200   80819

As you can see, I got the same results on HotSpot 1.6 as 1.7.

Last update: 2014.

Table of Contents

 About This Book

 Downloading and Installing JDK 1.8.0 on Windows

 Downloading and Installing JDK 1.7.0 on Windows

 java.lang.Runtime Class - The JVM Instance

 java.lang.System Class - The Operating System

 ClassLoader Class - Class Loaders

 Class Class - Class Reflections

 Sun's JVM - Java HotSpot VM

 JRockit JVM 28.2.7 by Oracle Corporation

 JVM Runtime Data Areas

 Memory Management and Garbage Collectors

►Garbage Collection Tests

 GCTest2.java - Garbage Collection Test Program

 640/400/40MB Test on HotSpot Client 1.7

 640/400/40MB Test on HotSpot Client 1.6

 640/400/40MB Test on JRockit 28.2

 441/400/40MB Test on JRockit 28.2

 1076/800/80MB Test on HotSpot Client 1.7

►1076/800/80MB Test on HotSpot Client 1.6

 1076/800/80MB Test on JRockit 28.2

 JVM Stack, Frame and Stack Overflow

 Thread Testing Program and Result

 CPU Impact of Multi-Thread Applications

 I/O Impact of Multi-Thread Applications

 CDS (Class Data Sharing)

 Micro Benchmark Runner and JVM Options

 Micro Benchmark Tests on "int" Operations

 Micro Benchmark Tests on "long" Operations

 Micro Benchmark Tests in JIT Compilation Mode

 Micro Benchmark Tests on "float" and "double" Operations

 Outdated Tutorials

 References

 PDF Printing Version