
https://docs.oracle.com/javase/8/docs/technotes/tools/unix/java.html
http://openjdk.java.net/jeps/122
-XX:+TraceClassLoading
Enables tracing of classes as they are loaded. By default, this option is disabled and classes are not traced.
常用
https://blog.sokolenko.me/2014/11/javavm-options-production.html
1 |
-server |
内存
XX:MinHeapFreeRatio
Sets the minimum allowed percentage of free heap space (0 to 100) after a GC event. If free heap space falls below this value, then the heap will be expanded. By default, this value is set to 40%.
-XX:MaxHeapFreeRatio
Sets the maximum allowed percentage of free heap space (0 to 100) after a GC event. If free heap space expands above this value, then the heap will be shrunk
-XX:NewRatio=ratio
Sets the ratio between young and old generation sizes. By default, this option is set to 2.
-XX:NewSize=size
- Sets the initial size (in bytes) of the heap for the young generation (nursery)
- The -XX:NewSize option is equivalent to -Xmn.
-XX:MaxPermSize=size
Sets the maximum permanent generation space size (in bytes). This option was deprecated in JDK 8, and superseded by the -XX:MaxMetaspaceSize option.
-XX:MaxMetaspaceSize=size
Sets the maximum amount of native memory that can be allocated for class metadata. By default, the size is not limited.
1 |
-XX:MaxMetaspaceSize=256m |
-XX:MetaspaceSize=size
Sets the size of the allocated class metadata space that will trigger a garbage collection the first time it is exceeded. This threshold for a garbage collection is increased or decreased depending on the amount of metadata used. The default size depends on the platform
-XX:CompressedClassSpaceSize=128m
江南白衣
-XX:+PrintFlagsFinal
打印参数值




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