The native Modifier : In java
applications, sometimes we will want to use a method that exists outside the JVM.
In this scenario, the native modifier can help, native modifier can only apply
to a method. Just as the abstract keyword, the native keyword indicates that the
implementation of the method exists elsewhere. In case of abstract, the
implementation of a method may exist in a subclass of the class in which the
abstract method is declared.
But in the case of native, the implementation of the method exists in a library outside the JVM. The native method is usually implemented in a non-Java language such as C or C++. Before a native method can be invoked, a library that contains the method must be loaded and that library is loaded by making the following system call:
System.loadLibrary("libraryName");
To declare a native method, precede the method with the native modifier, but do not define any body for the method. For example:
public native void Nativemethod() ;
After you declare a native method, you must write the native method and follow a complex series of steps to link it with your Java code. For example, the following code fragment presents an example of loading a library named NativeMethodDef which contains a method named NativeMethod():
But in the case of native, the implementation of the method exists in a library outside the JVM. The native method is usually implemented in a non-Java language such as C or C++. Before a native method can be invoked, a library that contains the method must be loaded and that library is loaded by making the following system call:
System.loadLibrary("libraryName");
To declare a native method, precede the method with the native modifier, but do not define any body for the method. For example:
public native void Nativemethod() ;
After you declare a native method, you must write the native method and follow a complex series of steps to link it with your Java code. For example, the following code fragment presents an example of loading a library named NativeMethodDef which contains a method named NativeMethod():
Java Tutorialslass NativeModifierExample
{
native void NativeMethod();
static
{
System.loadLibrary("NativeMethodDef");
}
}
Note that the library is loaded in a static code
block which suggest that the library is loaded at the class load time, so it is
there when a call to the native method is made. One can use the native method in
the same way as we use a non-native method. For example, the following two lines
of code would invoke the native method,NativeModifierExample obj = new NativeModifierExample();
obj.NativeMethod();
