Unable to execute DEX: Java heap space solution (how to add memory for eclipse.int)

Reprinted.
Http://blog.csdn.net/zengyangtech/article/details/7003379

Today, I encountered a problem while compiling a large project.

Unable to execute DEX: Java heap Space

There are two solutions:

1. Add memory to eclipse.int

2. Import jar files of the import project using Add User Library

Right-click Project-> build path-> Add library-> User libraries-> New-> just get a name-> Add jars-> OK

Remember to select user systemlibrary during adding

Eclipse. ini

-startupplugins/org.eclipse.equinox.launcher_1.0.201.R35x_v20090715.jar--launcher.libraryplugins/org.eclipse.equinox.launcher.win32.win32.x86_1.0.200.v20090519-showsplashorg.eclipse.platform--launcher.XXMaxPermSize256m-vmargs-Xms40m-Xmx256m

You can directly configure relevant parameters below

In the parameters-vmargs indicates setting JVM parameters, so the following are actually JVM parameters. First, let's take a look at the JVM memory management mechanism, and then explain the meaning of each parameter.

Heap and non-heap memory
According to the official statement: "A Java virtual machine has a heap. The heap is the runtime data area, and the memory of all class instances and arrays is allocated from this place. The heap is created when the Java Virtual Machine is started ." "Memory outside of the heap in JVM is called non-heap memory )". JVM manages two types of memory: heap and non-heap. In short, heap is the memory available for Java code and is reserved for developers. Non-heap is reserved for JVM, therefore, the method area, JVM internal processing or optimization of the required memory (such as the code cache after JIT compilation), each class structure (such as the runtime data pool, field and method data) the methods and constructor code are all in non-heap memory.
Heap Memory Allocation
The initial memory allocated by JVM is specified by-XMS. The default value is 1/64 of the physical memory. The maximum memory allocated by JVM is specified by-xmx. The default value is 1/4 of the physical memory. By default, when the free heap memory is less than 40%, the JVM will increase the heap until the maximum limit of-xmx. When the free heap memory is greater than 70%, the JVM will reduce the minimum limit of heap until-XMS. Therefore, the server generally sets-XMS and-xmx to be equal to each other to avoid adjusting the heap size after each GC.
Non-heap memory allocation
JVM uses-XX: permsize to set the non-heap memory initial value. The default value is 1/64 of the physical memory. The maximum non-heap memory size is set by XX: maxpermsize. The default value is 1/4 of the physical memory.
JVM memory limit (maximum)
First, the JVM memory is limited to the actual maximum physical memory. If the physical memory is infinitely large, the maximum JVM memory has a great relationship with the operating system. Simply put, although the 32-bit processor has a controllable memory space of 4 GB, the specific operating system will impose a limit, this limit is generally 2 GB-3 GB (1.5 GB-2 GB in windows and 2 GB-3 GB in Linux ), the 64-bit and above processors will not be limited.

Parameters are in the form of "item value". If there is a space in the middle, you need to wrap it. If there is a space in the value, you need to include it in double quotation marks. For example, we use the-VM c: \ Java \ jre1.6.0 \ bin \ javaw.exe parameter to set the virtual machine. In the eclipse. ini file, we need to write it as follows:

-VM
C: \ Java \ jre1.6.0 \ bin \ javaw.exe

Among them,-launcher. xxmaxpermsize (note that there are two connection lines at the top) and-XX: the meaning of maxpermsize.pdf is similar, except that the prefix is the parameter set when eclipse.exe is started, and the latter is the parameter in the JVM used by eclipse.