Java选项-Xmx代表什么？

Question

java -Xmx1024m filename

什么-Xmx意思？

Answer 1

看到这里:Java Tool Doc,它说,

-Xmx n
指定内存分配池的最大大小(以字节为单位).此值必须是1024的倍数大于2MB.附加字母k或K表示千字节,或m或M表示兆字节.默认值为64MB.此值的上限在Solaris 7和Solaris 8 SPARC平台上约为4000米,在Solaris 2.6和x86平台上为2000米,减去开销金额.例子:

           -Xmx83886080
           -Xmx81920k
           -Xmx80m

因此,简单来说,您将Java堆内存设置为可用内存最多1024 MB,而不是更多.

请注意,-Xmx和1024m之间没有空格

如果使用大写或小写,则无关紧要.例如:"-Xmx10G"和"-Xmx10g"完全相同.

Answer 2

C:\java -X

    -Xmixed           mixed mode execution (default)
    -Xint             interpreted mode execution only
    -Xbootclasspath:<directories and zip/jar files separated by ;>
                      set search path for bootstrap classes and resources
    -Xbootclasspath/a:<directories and zip/jar files separated by ;>
                      append to end of bootstrap class path
    -Xbootclasspath/p:<directories and zip/jar files separated by ;>
                      prepend in front of bootstrap class path
    -Xnoclassgc       disable class garbage collection
    -Xincgc           enable incremental garbage collection
    -Xloggc:<file>    log GC status to a file with time stamps
    -Xbatch           disable background compilation
    -Xms<size>        set initial Java heap size
    -Xmx<size>        set maximum Java heap size
    -Xss<size>        set java thread stack size
    -Xprof            output cpu profiling data
    -Xfuture          enable strictest checks, anticipating future default
    -Xrs              reduce use of OS signals by Java/VM (see documentation)
    -Xcheck:jni       perform additional checks for JNI functions
    -Xshare:off       do not attempt to use shared class data
    -Xshare:auto      use shared class data if possible (default)
    -Xshare:on        require using shared class data, otherwise fail.

The -X options are non-standard and subject to change without notice.

Answer 3

-Xmx选项更改VM的最大堆空间.java -Xmx1024m表示VM最多可以分配1024 MB.通俗地说,这意味着应用程序最多可以使用1024MB内存.

Answer 4

应用程序的最大堆使用率为1024 MB

Answer 5

-Xmx 设置最大堆大小