java.lang.OutOfMemoryError: GC overhead limit exceeded

 

I am getting this error in a program that creates several (hundreds of thousands) HashMap objects with a few (15-20) text entries each. These Strings have all to be collected (without breaking up into smaller amounts) before being submitted to a database.

According to Sun, the error happens "if too much time is being spent in garbage collection: if more than 98% of the total time is spent in garbage collection and less than 2% of the heap is recovered, an OutOfMemoryError will be thrown.".

Apparently, one could use the command line to pass arguments to the JVM for

  • Increasing the heap size, via "-Xmx1024m" (or more), or
  • Disabling the error check altogether, via "-XX:-UseGCOverheadLimit".

    • The first approach works fine, the second ends up in another java.lang.OutOfMemoryError, this time about the heap.

    So, question: is there any programmatic alternative to this, for the particular use case (ie, several small HashMap objects)? If I use the HashMap clear() method, for instance, the problem goes away, but so do the data stored in the HashMap! :-)

    The issue is also discussed in a related topic in StackOverflow.

    You're essentially running out of memory to run the process smoothly. Options that come to mind:

  • Specify more memory like you mentioned, try something in between like -Xmx512m first
  • Work with smaller batches of HashMap objects to process at once if possible
  • If you have a lot of duplicate strings, use String.intern() on them before putting them into the HashMap
  • Use the HashMap(int initialCapacity, float loadFactor) constructor to tune for your case

    • The following worked for me. Just add the following snippet: 

    dexOptions {
        javaMaxHeapSize "4g"
}

    To your build.gradle : 

    android {
    compileSdkVersion 23
    buildToolsVersion '23.0.1'

    defaultConfig {
        applicationId "yourpackage"
        minSdkVersion 14
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"

        multiDexEnabled true
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    packagingOptions {

    }

    dexOptions {
        javaMaxHeapSize "4g"
    }
}

    @takrl: The default setting for this option is: 

    java -XX:+UseConcMarkSweepGC

    which means, this option is not active by default. So when you say you used the option " +XX:UseConcMarkSweepGC " I assume you were using this syntax: 

    java -XX:+UseConcMarkSweepGC

    which means you were explicitly activating this option. For the correct syntax and default settings of Java HotSpot VM Options @ this document

    链接地址: http://www.djcxy.com/p/82950.html

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