Java KeyWords?
Used to define a block of statements for a block defined previously by the try keyword. The finally block is executed after execution exits the try block and any associated catch clauses regardless of whether an exception was thrown or caught, or execution left method in the middle of the try or catch blocks using the return keyword.
As of J2SE 5.0, the for keyword can also be used to create a so-called "enhanced for loop",[14] which specifies an array or Iterable object; each iteration of the loop executes the associated block of statements using a different element in the array or Iterable.[13]
implements
Included in a class declaration to specify one or more interfaces that are implemented by the current class. A class inherits the types and abstract methods declared by the interfaces.
strictfp (as of J2SE 1.2)
A Java keyword used to restrict the precision and rounding of floating point calculations to ensure portability.[10]
Also used to specify a lower bound on a type parameter in Generics.
char
Defines a character variable capable of holding any character of the java source file's character set (NB: Physical storage may exceed one byte).class
A type that defines the implementation of a particular kind of object. A class definition defines instance and class fields, methods, and inner classes as well as specifying the interfaces the class implements and the immediate superclass of the class. If the superclass is not explicitly specified, the superclass is implicitly Object. The class keyword can also be used in the form Class.class to get a Class object without needing an instance of that class. For example, String.class can be used instead of doing new String().getClass().
const
Although reserved as a keyword in Java, const is not used and has no function.[2][1] For defining constants in java, see the 'final' reserved word.continue
Used to resume program execution at the end of the current loop body. If followed by a label, continue resumes execution at the end of the enclosing labeled loop body.default
The default keyword can optionally be used in a switch statement to label a block of statements to be executed if no case matches the specified value; see switch.[3][4] Alternatively, the default keyword can also be used to declare default values in a Java annotation. From Java 8 onwards, the default keyword is also used to specify that a method in an interface provides the default implementation of an optional method.do
The do keyword is used in conjunction with while to create a do-while loop, which executes a block of statements associated with the loop and then tests a boolean expression associated with the while. If the expression evaluates to true, the block is executed again; this continues until the expression evaluates to false.double
The double keyword is used to declare a variable that can hold a 64-bit double precision IEEE 754 floating-point number. This keyword is also used to declare that a method returns a value of the primitive type double.else
The else keyword is used in conjunction with if to create an if-else statement, which tests a boolean expression; if the expression evaluates to true, the block of statements associated with the if are evaluated; if it evaluates to false, the block of statements associated with the else are evaluated.enum
A Java keyword used to declare an enumerated type. Enumerations extend the base class Enum.extends
Used in a class declaration to specify the superclass; used in an interface declaration to specify one or more superinterfaces. Class X extends class Y to add functionality, either by adding fields or methods to class Y, or by overriding methods of class Y. An interface Z extends one or more interfaces by adding methods. Class X is said to be a subclass of class Y; Interface Z is said to be a subinterface of the interfaces it extends.final
Define an entity once that cannot be changed nor derived from later. More specifically: a final class cannot be subclassed, a final method cannot be overridden, and a final variable can occur at most once as a left-hand expression on an executed command. All methods in a final class are implicitly final.
finally
Used to define a block of statements for a block defined previously by the try keyword. The finally block is executed after execution exits the try block and any associated catch clauses regardless of whether an exception was thrown or caught, or execution left method in the middle of the try or catch blocks using the return keyword.
float
The float keyword is used to declare a variable that can hold a 32-bit single precision IEEE 754 floating-point number.[7][8] This keyword is also used to declare that a method returns a value of the primitive type float.[9][10]for
The for keyword is used to create a for loop, which specifies a variable initialization, a boolean expression, and an incrementation. The variable initialization is performed first, and then the boolean expression is evaluated. If the expression evaluates to true, the block of statements associated with the loop are executed, and then the incrementation is performed. The boolean expression is then evaluated again; this continues until the expression evaluates to false.[13]As of J2SE 5.0, the for keyword can also be used to create a so-called "enhanced for loop",[14] which specifies an array or Iterable object; each iteration of the loop executes the associated block of statements using a different element in the array or Iterable.[13]
goto
Although reserved as a keyword in Java, goto is not used and has no function.if
The if keyword is used to create an if statement, which tests a boolean expression; if the expression evaluates to true, the block of statements associated with the if statement is executed. This keyword can also be used to create an if-else statement; see else.implements
Included in a class declaration to specify one or more interfaces that are implemented by the current class. A class inherits the types and abstract methods declared by the interfaces.
import
Used at the beginning of a source file to specify classes or entire Java packages to be referred to later without including their package names in the reference. Since J2SE 5.0, import statements can import static members of a class.instanceof
A binary operator that takes an object reference as its first operand and a class or interface as its second operand and produces a boolean result. The instanceof operator evaluates to true if and only if the runtime type of the object is assignment compatible with the class or interface.int
The int keyword is used to declare a variable that can hold a 32-bit signed two's complement integer.[ This keyword is also used to declare that a method returns a value of the primitive type int.interface
Used to declare a special type of class that only contains abstract methods, constant (static final) fields and static interfaces. It can later be implemented by classes that declare the interface with the implements keyword.long
The long keyword is used to declare a variable that can hold a 64-bit signed two's complement integer.This keyword is also used to declare that a method returns a value of the primitive type long.[native
Used in method declarations to specify that the method is not implemented in the same Java source file, but rather in another language.new
Used to create an instance of a class or array object. Using keyword for this end is not completely necessary (as exemplified by Scala), though it serves two purposes: it enables the existence of different namespace for methods and class names, it defines statically and locally that a fresh object is indeed created, and of what runtime type it is (arguably introducing dependency into the code).package
A group of types. Packages are declared with the package keyword.private
The private keyword is used in the declaration of a method, field, or inner class; private members can only be accessed by other members of their own class.[15]protected
The protected keyword is used in the declaration of a method, field, or inner class; protected members can only be accessed by members of their own class, that class's subclasses or classes from the same package.public
The public keyword is used in the declaration of a class, method, or field; public classes, methods, and fields can be accessed by the members of any class.return
Used to finish the execution of a method. It can be followed by a value required by the method definition that is returned to the caller.short
The short keyword is used to declare a field that can hold a 16-bit signed two's complement integer.[ This keyword is also used to declare that a method returns a value of the primitive type short.static
Used to declare a field, method, or inner class as a class field. Classes maintain one copy of class fields regardless of how many instances exist of that class. static also is used to define a method as a class method. Class methods are bound to the class instead of to a specific instance, and can only operate on class fields. (Classes and interfaces declared as static members of another class or interface are actually top-level classes and are not inner classes.)strictfp (as of J2SE 1.2)
A Java keyword used to restrict the precision and rounding of floating point calculations to ensure portability.[10]
super
Used to access members of a class inherited by the class in which it appears. Allows a subclass to access overridden methods and hidden members of its superclass. The super keyword is also used to forward a call from a constructor to a constructor in the superclass.Also used to specify a lower bound on a type parameter in Generics.
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