Local variables Instance variables Class/static variables
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Local variables are declared within methods, constructors, or blocks and only visible within those scopes. They are stored on the stack and have no default value. Instance variables are declared within a class but outside of methods and hold object state visible throughout the class. They are stored on the heap and have default values of null, 0, or false. Class/static variables are associated with the class, not object instances, and can be accessed before object creation. The presentation discusses the different types of variables in Java including local, instance, and class variables as well as their scopes, memory locations, default values, and examples.
Local variables Instance variables Class/static variables
- 1. TODAY MY PRESENTATION TOPIC IS TYPES OF VARIABLES
- 2. Variable • A variable provides us wit h named st orage t hat our programs can manipulate.
- 3. There are three kinds of variables in java • Local variables • Instance variables • Class/static variables
- 4. Local variables • Local variables are declared in methods, constructors, or blocks. • Local variables are created when the method, constructor or block is entered and the variable • will be destroyed once it exits the method, constructor or block. • Access modifiers cannot be used for local variables.
- 5. • Local variables are visible only within the declared method, constructor or block. • Local variables are implemented at stack level internally. • There is no default value for local variables so local variables should be declared and an initial • value should be assigned before the first use.
- 6. Example
- 7. Instance variables • Instance variables are declared in a class, but outside a method, constructor or any block. • Instance variables hold values that must be referenced by more than one method, constructor or block, or essential parts of an object's state that must be present throughout the class. • Instance variables can be declared in class level before or after use. • Access modifiers can be given for instance variables.
- 8. • The instance variables are visible for all methods, constructors and block in the class. • Normally, it is recommended to make these variables private accesslevel. However visibility for subclasses can be given for these variables with the use of access modifiers. • Instance variables have default values. For numbers the default value is 0, for Booleans it is false and for object references it is null. Values can be assigned during the declaration or within the constructor.
- 9. Example
- 10. THANK YOU