java Flashcards
What are supported platforms by Java?
Mac OS, Windows, Linux, Unix
List five features of Java
1 OOP 2 Robust 3 Interpreted 4 Multithreaded 5 Multi Platform
Why is Java Architecture neutral?
Its compiler creates an architecture neutral object file format..
The compiled source code can be executed on many preprocessors with Java runtime System.
How does Java enables High Performance?
Java uses Just In Time Compiler. This compiler converters java bycode to machine specific instruction.
List two Java IDE
Eclipse
Netbeans
What is an object?
A runtime entity whose state is in stored in fields and whose behaviours is shown via the methods.
What is a class?
A blueprint from which objects are created.
It contains the fields and methods to describe the state of the object.
What type of variables can a class consists of ?
- Local
- Instance variable
- Class variables
What is a local variable?
Variables created inside the method, blocks or constructors.
The variable will be created and initialized within this..
What are instance variable
The variables created within a class but outside the method. These variables are instantiated when the class is loaded.
When are the instance variables initialized?
when the class is loaded
What is a class variable?
A variable created within a class but outside any methods and declared with a static keyword.
What is singleton class
It controls object creation generally limiting the number to one but allowing the flexibility to change and allowing more creation of objects should they be required.
What is a constructor?
Used to create an instance of a class.
List three steps of creating an object?
- Object is declared
- Instantiated
- Initialized
What is the default for float/double datatype?
- 0.0f
- 0.0d
What is a static variable?
Same as class variables. They are created within a class but outside methods, constructors, blocks with the static keyword.
What is access modifier?
that controls access to classes, variables, methods, etc
What is protected access modifier?
variables, methods and constructors which are declared protected can be accessed by the subclass of the other package and any class within the same package of the protected member’s class.
What is synchronized ?
An modifier that controls an object’s access to shared resource.
Which Operator is at the highest precedence?
()
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