1. Memory Architecture
Java program is running, you need to allocate space in memory to improve operational efficiency, space has been divided into different areas, because each one has a specific area of data processing methods and memory management.
Stack memory
· Used to store local variables, when the data used up, less space will be automatically released,
Heap
Arrays and objects, instances established by Bw are stored in the heap memory,
• Each entity has a memory address
· Entities variable has a default initialization value
· Entity is not being used, it will be garbage collected within the time uncertain
Zhejiang heart of this area law enforcement by law area. In material damage
2. Members and local variables
Fan Figure role
Member variables acting on the entire class.
Variables circumferential portion acts on the function, or statement.
In memory location:
Member variables: in heap memory, because the object exists, exists only in memory,
Local variables: A stack-based memory.
3. anonymous object
Anonymous object is a simplified form of objects
Anonymous objects used in two cases
• When an object method is invoked only once
· Anonymous objects can be passed as actual parameters
4. Static: static
Usage: is a modifier for modifying member (member variables, member functions)
When the members are static modification, on more than one call, except that the object can be invoked outside, you can also directly call the class name
Static Features:
1, with the loading and load the class,
He says: Static will disappear with the disappearance of class, describe its longest life cycle
2, in preference to the object exists
3, is shared by all objects
4, can be directly invoked by class name
Instance variables and class variables difference:
1, storage location
Class variables as present in the class loading zone method,
With the establishment of an object instance variables exist in the heap memory
2, the life cycle
Class variables longest life cycle, with the disappearance of class disappear
With the disappearance of the life cycle of an instance variable objects disappear
6. Static Precautions
1, static methods can only access static members
Non-static method can access both static can also access non-static
2, static method can not define this, super keyword
Because static precedence over the object exists, it appears this may not be a static method
Static pros and cons
Lee at: shared data objects stored in a separate space, space-saving, is not necessary in each object are stored in a
It can be directly invoked by class name.
Drawbacks: long life cycle
Access appears limitations. (Static is good, can only access static