OOM：Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

[DESCRIPTION]

在编译core.jar或framework.jar很容易引起java OOM异常

错误信息

Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

[KEYWORD]

out of memory

OOM

core.jar

framework.jar

signapk.jar

[SOLUTION]

原因:

1. Jar中塞了很多代码，消耗更多memory，可能导致heap溢出

2. 编译机器内存较小

解决方法：

修改build/core/definitions.mk里的transform-classes.jar-to-dex这function里的JXmx: 加大-JXmx1536M => 2048M (1024的倍数)

很多地方会有设置Xmx，如果遇到java OOM需要查看log看哪个地方溢出，然后在做调整

其他出现OOM的例子：

编译T卡升级包报错(./mk otapackage)，提示内存不足

log如下：

building image from target_files RECOVERY...

  running:  mkbootfs /tmp/targetfiles-kRbwor/RECOVERY/RAMDISK

  running:  minigzip

  running:  mkbootimg --kernel /tmp/targetfiles-kRbwor/RECOVERY/kernel --ramdisk /tmp/targetfiles-kRbwor/RECOVERY/ramdisk --output /tmp/tmpxEiPed

  running:  imgdiff /tmp/tmpY36O6w /tmp/tmpxtUmXd /tmp/tmp11WNY3

[SEC OTA] Adding security version (WriteFullOTAPackage)

  running:  openssl pkcs8 -in build/target/product/security/testkey.pk8 -inform DER -nocrypt

  running:  java -Xmx2048m -jar out/host/linux-x86/framework/signapk.jar -w build/target/product/security/testkey.x509.pem build/target/product/security/testkey.pk8 /tmp/tmpvmjnCf out/target/product/ics2/htt77_ics2-ota-user.xxx.zip

   ERROR: signapk.jar failed: return code 1

make[2]: *** [out/target/product/ics2/ics2-ota-user.xxx.zip] Error 1

分析：

此问题是运行signapk.jar导致内存不足，需要修改下参数：

在build/tools/releasetools/common.py里的SignFile函数中，加大-Xmx

cmd = ["java", "-Xmx512m", "-jar",

           os.path.join(OPTIONS.search_path, "framework", "signapk.jar")]

修改为：

cmd = ["java", "-Xmx1024m", "-jar",

           os.path.join(OPTIONS.search_path, "framework", "signapk.jar")]