jprofiler Viewer memory leak

In a recent work by JProfiler solve the problem of a memory leak, will now step of detecting and recorded some analysts, may have been used as reference for future encountered similar problems.

Operating environment:

Tomcat6，jdk6，JProfiler8

Memory leak phenomenon:

1. Perform batch operations some time in the server, find a memory instead of falling; even after gc, the memory can not be fully released;

2. Unless restart tomcat server memory is never freed, repeated these actions will result in no memory available, tomcat died;

Use check for memory leaks steps JProfiler:

1. Initialize the test environment:

Switch to the "Live Memory -> All Objects" tab, you can see the object in the current tomcat.

Before performing the operation, you need to run the "Run GC", the jvm for memory recovery, clean up invalid object;

In order to facilitate growth of the comparison memory, click "Mark Current" button, to the current memory usage as a reference;

It is displayed after clicking "Difference" column, which lists the number of objects changes and rate of change;

2. Open the memory record:

Click "Start Recordings" button to start recording. The main purpose of the implementation of this step is to following "Heap Walker", set up a monitoring interval; if you do not record the words, "Heap Walker" will analyze all memory jvm virtual machine that is time-consuming and may not accurately find the cause of memory leaks.

3. Perform the operations performed GC;

Performing a memory operation may cause leaks, for executing the memory recovery;

You can click on the "update" button to update the view;

After performing garbage collection target, still exists in memory there may be a leak of the object; in the following figure, instance count in the red sector object can not be recycled, difference column lists the number of objects increase and growth; for example a String , the increase in the operation target 31751, an increase of 14%, these objects will then be observed in HeapWalker, the analysis of which objects are leaking;

Objects are generally caused by leakage include: String, char [], HashMap, these objects need to focus on the next;