This
Optimization of Java is a collection of
optimization techniques used in
Java programming language.
In Java, object creations are so expensive compared with other compiled object-oriented programming language. It is because in Java, object creation involves:
- memory allocation[?] from heap, which may cause garbage collection when free space is insufficient.
- calling constructures
Because Java compiler cannot be completely sure about which method will be called before runtime, each method call involves looking up a method. Use of small and simple methods that are called frequently can be quite expensive. If possible, embed code of such method directly to the point of call.
Myths
There are some myths in performance tuning of Java programs.
-
final
modifer with methods or classes reduces the overhead of call of methods - Because the Java compiler cannot know which class will be loaded at runtime, it cannot in-line-expand[?] the methods regardless if they have final
or not.
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