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  Here are several examples of variable declarations of various types. Note that some include an initialization. int a, b, c; // declares three ints, a, b, and c.  int d = 3, e, f = 5; // declares three more ints, initializing  // d and f. byte z = 22; // initializes z.  double pi = 3.14159; // declares an approximation of pi.  char x = 'x'; // the variable x has the value 'x'.  This chapter will explain various variable types available in Java Language. There are three kinds of variables in Java:    Local variables    Instance variables    Class/static variables 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.    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 JAVA Java is an Object-Oriented Language. As a language that has the Object Oriented feature, Java supports the following fundamental concepts:      Polymorphism    Inheritance    Encapsulation    Abstraction    Classes    Objects    Instance    Method    Message Parsing  Here are several examples of variable declarations of various types. Note that some include an initialization. int a, b, c; // declares three ints, a, b, and c.  int d = 3, e, f = 5; // declares three more ints, initializing  // d and f. byte z = 22; // initializes z.  double pi = 3.14159; // declares an approximation of pi.  char x = 'x'; // the variable x has the value 'x'.  This chapter will explain various variable types available in Java Language. There are three kinds of variables in Java:    Local variables    Instance variables    Class/static variables 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.    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 In this chapter, we will look into the concepts Classes and Objects.    Object -  Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors -wagging, barking, eating. An object is an instance of a class.    Class -  A class can be defined as a template/blue print that describes the behaviors/states that object of its type support. Java - Library Classes    Here is the list of classes of package java.lang . These classes are very important to know for a Java programmer. Click a class link to know more detail about that class. For a further drill, you can refer standard Java documentation. SN Methods with Description 1 Boolean Boolean  Here are several examples of variable declarations of various types. Note that some include an initialization. int a, b, c; // declares three ints, a, b, and c.  int d = 3, e, f = 5; // declares three more ints, initializing  // d and f. byte z = 22; // initializes z.  double pi = 3.14159; // declares an approximation of pi.  char x = 'x'; // the variable x has the value 'x'.  This chapter will explain various variable types available in Java Language. There are three kinds of variables in Java:    Local variables    Instance variables    Class/static variables 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.    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 2 Byte The Byte class wraps a value of primitive type byte in an object. 3 Character The Character class wraps a value of the primitive type char in an object. 4 Class Instances of the class Class represent classes and interfaces in a running Java application. 5 ClassLoader A class loader is an object that is responsible for loading classes. 6 Compiler The Compiler class is provided to support Java-to-native-code compilers and related services. 7 Double The Double class wraps a value of the primitive type double in an object. 8 Float The Float class wraps a value of primitive type float in an object. 9 Integer  Here are several examples of variable declarations of various types. Note that some include an initialization. int a, b, c; // declares three ints, a, b, and c.  int d = 3, e, f = 5; // declares three more ints, initializing  // d and f. byte z = 22; // initializes z.  double pi = 3.14159; // declares an approximation of pi.  char x = 'x'; // the variable x has the value 'x'.  This chapter will explain various variable types available in Java Language. There are three kinds of variables in Java:    Local variables    Instance variables    Class/static variables 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.    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 The Integer class wraps a value of the primitive type int in an object. 10 Long The Long class wraps a value of the primitive type long in an object. 11 Math The class Math contains methods for performing basic numeric operations such as the elementary exponential, logarithm, square root, and trigonometric functions. 12  Number The abstract class Number is the superclass of classes BigDecimal, BigInteger, Byte, Double, Float, Integer, Long, and Short. 13 Object Class Object is the root of the class hierarchy. 14 Package Package objects contain version information about the implementation and specification of a Java package. 15 Process The Runtime.exec methods create a native process and return an instance of a subclass of
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