Common JVM Tuning Flags

The JVM has sensible defaults, but for demanding services you sometimes adjust heap size, the garbage collector, and JIT behavior.

Tuning is a last step: profile first, fix the code, then reach for flags only when measurements justify them.

The two most common flags set heap bounds:

• -Xms — initial heap size.
• -Xmx — maximum heap size.

Example: java -Xms512m -Xmx2g MyApp. Setting -Xms equal to -Xmx avoids resize pauses in long-running servers.