final can be used to mark a variable "unchangeable"
private final String name = "foo"; //the reference name can never change
final can also make a method not "overrideable"
public final String toString() { return "NULL"; }
finally is used in a try/catch statement to execute code "always"
lock.lock();
try {
//do stuff
} catch (SomeException se) {
//handle se
} finally {
lock.unlock(); //always executed, even if Exception or Error or se
}
finalize is called when an object is garbage collected. You rarely need to override it. An example:
public void finalize() {
//free resources (e.g. unallocate memory)
super.finalize();
}
Final:
A final class variable is one whose value cannot be changed.
A final method is one that cannot be overriden (define with new behavior in subclasses).
A final class cannot be inherited.
When a class is marked final, it cannot be subclassed. When a method is marked final, it cannot be overridden by the subclass. And when a field is marked final, its value once set, cannot be reset.
Finally:
It is a block of statements that definitely executes after the try catch block.
finally is the last clause in a try...catch block. It is a block of statements that is executed irrespective if or if not an exception was caught in the preceding try block.
Finalize:
This method will be executed when the object is garbage-collected. finalize is a reserved method in Java, which can be overridden by classes containing code to release any expensive resources being held to by the object. Expensive resources include, native peer objects, file/device/database connections.
0 comments:
Post a Comment