Method inlining can significantly improve method call performance. Any method that is final is a potential candidate for inlining.
The inline feature is available on the iSeries™ server through the javac -o option at compilation time. The size of your class files and transformed Java™ program increases if you use the javac -o option. You should consider both the space and performance characteristics of your application when using the -o option.
The Java transformer enables inlining for optimization level 30 and optimization level 40. Optimization level 30 enables some inlining of final methods within a single class. Optimization level 40 enables inlining of final methods within a ZIP file or JAR file. You can control method inlining with the AllowInlining and NoAllowInlining LICOPT parameter strings. The iSeries interpreter does not perform method inlining.
The Just-In-Time (JIT) compiler also performs inlining of most final methods. This is done automatically whenever the JIT compiler is active and it determines that inlining will be beneficial.