Java Native Interface¶

1. You can call native code (typically C, C++ or Fortran) in Java using the Java Native Interface (JNI). For the code implemented in native code, you must use keyword "native" to tell the compiler that it is implemented outside Java. Also, you should surround the Java code which load the compile native code in static{}

Tips and Traps¶

1. A static method cannot be abstract in Java. For refer to this discussion on Stackoverflow for rationale behind it. If you need the two together, what you are looking is probably singleton object with inheritance.

2. Singleton objects are more flexible and useful than static methods in Java. Please refer to Singleton Pattern Versus Static Class

An implementation of the singleton pattern must:

• ensure that only one instance of the singleton class ever exists;
• and provide global access to that instance.

Typically, this is done by:

• declaring all constructors of the class to be private;
• and providing a static method that returns a reference to the instance.

The instance is usually stored as a private static variable; the instance is created when the variable is initialized, at some point before the static method is first called. The following is a sample implementation written in Java.

Comments¶

1. String is a immutable class in Java. Extensive operations on strings (e.g., + in a big loop) is usually very slow before Java 7 (the + operator is optimized by the compiler automatically starting from Java 7). To avoid this problem (in older versions of Java), you can use the StringBuilder