java - 增加 Java 堆大小的速度

Question

我需要将 Java 堆大小增加到 2GB RAM。为了做同样的事情，我以用户身份使用了命令(我没有以 root 用户身份执行此操作):

$ export JVM_ARGS="-Xmx2048m"

但是，java堆大小并没有增加。

$ java -XX:+PrintFlagsFinal -version | grep -iE 'HeapSize|PermSize|ThreadStackSize'
    uintx AdaptivePermSizeWeight                    = 20              {product}           
     intx CompilerThreadStackSize                   = 0               {pd product}        
    uintx ErgoHeapSizeLimit                         = 0               {product}           
    uintx HeapSizePerGCThread                       = 87241520        {product}           
    uintx InitialHeapSize                          := 1054841216      {product}           
    uintx LargePageHeapSizeThreshold                = 134217728       {product}           
    uintx MaxHeapSize                              := 16877879296     {product}           
    uintx MaxPermSize                               = 174063616       {pd product}        
    uintx PermSize                                  = 21757952        {pd product}        
     intx ThreadStackSize                           = 1024            {pd product}        
     intx VMThreadStackSize                         = 1024            {pd product}        
java version "1.7.0_75"
OpenJDK Runtime Environment (rhel-2.5.4.0.el6_6-x86_64 u75-b13)
OpenJDK 64-Bit Server VM (build 24.75-b04, mixed mode)

有人可以建议我哪里出错了吗？

Answer 1

环境变量的名称是JAVA_TOOL_OPTIONS :

$ export JAVA_TOOL_OPTIONS='-Xmx2G'
$ java -XX:+PrintFlagsFinal -version | grep -iE 'MaxHeapSize'
Picked up JAVA_TOOL_OPTIONS: -Xmx2G
    uintx MaxHeapSize                              := 2147483648                          {product}
openjdk version "1.8.0_40-internal"
OpenJDK Runtime Environment (build 1.8.0_40-internal-b27)
OpenJDK 64-Bit Server VM (build 25.40-b25, mixed mode)