Java Performance Tuning

Performance Checklist

Most of these suggestions apply only after a bottleneck has been identified:

• Ensure that performance tests are run with the same amount of I/O as the expected finished application. Specifically, turn off any extra logging, tracing, and debugging I/O.

• Use Runtime.traceMethodCalls() , when supported, to count I/O calls.

  • Redefine the I/O classes to count I/O calls if necessary.

  • Include logging statements next to all basic I/O calls in the application.

• Parallelize I/O by splitting data into multiple files.

• Execute I/O in a background thread.

• Avoid the filesystem file-growing overhead by preallocating files.

• Try to minimize the number of I/O calls.

  • Buffer to reduce the number of I/O operations by increasing the amount of data transfer each I/O operation executes.

  • Cache to replace repeated I/O operations with much faster memory or local disk access.

  • Avoid or reduce I/O calls in loops.

  • Replace System.out and System.err with customized PrintStream classes to control console output.

  • Use logger objects for tight control in specifying logging destinations.

  • Try to eliminate duplicate and unproductive I/O statements.

  • Keep files open and navigate around them rather than repeatedly opening and closing the files.

• Consider optimizing the Java byte-to-char (and char-to-byte) conversion.

• Handle serializing explicitly, rather than using default serialization mechanisms.

  • Use transient fields to avoid serialization.

  • Use the java.io.Externalizable interface if overriding the default serialization ...