Reducing memory consumption in Java [closed]

Question

I have worked with some projects where achieving better performance and reducing memory consumption has been the primary goal. But believe me it has already been hard to control the memory consumption in Java.

This wiki page, says on "Java Program Speed" Java is in some cases equal to C++ on low-level and numeric benchmarks.

These statistics do not really show a major difference in time computation Performance benchmark. However, the memory usage in Java is quite higher than C++, since there is an 8-byte overhead for each object and 12-byte for each array in Java (32-bit; twice as much in 64-bit java) as mentioned in above wiki link.

Now the question is what all measures people take to minimize the memory utilization in Java?

Please note that I am much concerned about memory than performance, since I cannot think of any better ways than "writing better programs" and "correctly tuning memory in JDK"

Answer 1

Depending on your what you are working on you can benefit from different programming practices such as:

• Limiting the amount of variables that you initialize way before actually using them.
  • Just a general good coding tip. A variable that has been initialized and isn't needed for awhile is holding on to memory that isn't needed yet which may be wasting resources.
• Object caching via static objects where applicable.
  • I've used this before in reflection heavy applications where I need to get the list of members on an object within a loop and it can help performance considerably depending on the situation where it may be needed.
• Object pooling where applicable
  • http://www.javaworld.com/jw-06-1998/jw-06-object-pool.html
• If you are writing a multi-threaded application you can utilize thread pooling in order to gain performance by limiting the amount of work in creating and launching new threads.
  • http://www.ibm.com/developerworks/library/j-jtp0730/