In java, all aggregate data types and arrays are derived from the ancestor class Object. The Object class provides common functionality desirable for an aggregate datum or an array in a computing environment.
- Monitor Lock
An Object instance maintains an intrinsic lock which can be used in conjunction of synchronized keyword in multi-access context to guarantee exclusive access to the critical section as shown below.
public void do() {
synchronized(this) {
.../* critical section */
}
}
- Runtime class type tracking
The generic Class instance of a class/interface provides an inside view of the aggregate date type. A program may obtain the Class object for an Object and its subclass instance, with which, precise information about the fields, constructor, annotation, methods, etc. may be queried.
- String representation of an instance
The toString() is widely used for printout.
- Instance Clone
Used for instance copy.
- finalize method
Overridable method invoked before garbage collection.
- Equality Test
Used to test another instance is equal to this one.
- Hash code
Used for Hash indexing.
charleszblog 