查看当前JRE默认堆大小（default Heap size）

 下面两个命令用于查看当前JRE默认的堆大小，该方法适用于Java 6u20以及之后版本。

 

 

# 使用-server

java -server -XX:+UnlockDiagnosticVMOptions -XX:+PrintFlagsFinal -version | grep -i heapsize

uintx ErgoHeapSizeLimit = 0 {product}
uintx InitialHeapSize := 519327936 {product}
uintx LargePageHeapSizeThreshold = 134217728 {product}
uintx MaxHeapSize := 8311013376 {product}
java version "1.6.0_27-ea"
Java(TM) SE Runtime Environment (build 1.6.0_27-ea-b01)
Java HotSpot(TM) 64-Bit Server VM (build 20.2-b01, mixed mode)

 

 

# 使用-client
java -client -XX:+UnlockDiagnosticVMOptions -XX:+PrintFlagsFinal -version | grep -i heapsize

uintx ErgoHeapSizeLimit = 0 {product}
uintx InitialHeapSize := 519327936 {product}
uintx LargePageHeapSizeThreshold = 134217728 {product}
uintx MaxHeapSize := 8311013376 {product}
java version "1.6.0_27-ea"
Java(TM) SE Runtime Environment (build 1.6.0_27-ea-b01)
Java HotSpot(TM) 64-Bit Server VM (build 20.2-b01, mixed mode)

 

参考：

http://dow.ngra.de/2011/01/12/what-are-the-default-xmx-and-xms-values/

 

 

-- heipark