Java – Glossary of Terms

JAVA GLOSSARY OF TERMS

Access specifier – These are keywords which define the accessibility of the function, they can either be public, private or protected, if nothing is mentioned then by default it is ‘friendly’ friendly is not a keyword.

Accessor / Getter method – It is a method that only access and return the value of a data-member of the class, such methods are pure in nature and generally return type in nature.

Actual parameters – Parameters that appear at the point of function invocation or function call are called Actual parameters.

API (Application Programming Interface) – consists of libraries of pre compiled code that programmers can use in their application and programs for designing softwares. Hence we can say that Java API consists of functions and variables that programmers can reuse. It is a part of JDK.

Argument / Parameter list – This is a comma separated list of variables along with associated data types. This list can also be empty which indicates the function is non–argumentative.

Arguments – The values which are passed to the method during its invocation from the caller.

Attribute – The characteristics which makes every object having its own identity to make them distinguished from each other is known as an attribute,

Base class – It is a class which is inherited by another class.

Binary file – store information in a form of bytes.

Block- It is a group of zero or more statements between balanced braces and can be used anywhere a single statement is allowed.

Blue J –  Blue-J is an Integrated Development Environment (IDE) used for writing, editing, compiling, testing, executing and debugging Java programs, developed mainly for educational purposes, but also suitable for small-scale software development. Blue J was initially designed at University of Kent by David Barns and Michael Kollins.

break – It is an unconditional jump statement which is used to terminate the loop or switch case, when the condition is satisfied, it’s a keyword and hence should be written in lowercase

Buffer – is a high speed temporary storage, which is also sometimes referred as cache.

BufferedReader- It is a class that buffers the input and improves the performance of IO in Java

Byte Code – is an intermediate code that consists of a set of pseudo machine language instructions that are understood by the JVM and are independent of the underlying hardware, it has an extension name of *.class

Byte stream classes – They are built up to provide the functionality of reading and writing bytes. They help in transmitting data (bytes) in one direction. They are thus useful in Input-Output operation.

Character – It is a token which is a distinctive mark or symbol, alphabets (small or capital) or digits.

Character stream classes – They are built up to provide the functionality of reading and writing characters. They help in transmitting data (characters) in one direction. They are thus useful in Input-Output operation.

Class – It is a blueprint that represents a set or a collection of objects which share common characteristics and behaviour.

Coercion – Implicit data type conversion is termed as coercion in which the data gets converted from lower type to its higher type without any intervention of user.

Compile time error – Error that the compiler can detect during compilation, all Syntax errors are Compile time errors.

Compiler – The software which converts high level language instructions to machine level language at once.

Compound Statement – Is a set of multiple statement written within braces balanced { } is called a compound statement, it is also referred as a Block

Concatenation – The process of adding or appending a string at the end of another string.

Constructor – It is a member method of a class which has same name as that of a class; has no return type not even void, used to initialize the instance variables of a class, and gets invoked automatically as soon as the object of the class is created.

continue – is a keyword which is used to skip the current iteration and go for the next iteration, when the condition is satisfied within the program.

Dangling else Problem – The nested if – else statement introduces a source of potential ambiguity referred to as dangling else problem. This problem arises when in a nested if statement, number of ifs is more than the number of else clauses. The question arises, with which if does the additional else clause property match-up.

Data Abstraction – The act of representing only essential features without including its background details is called Data Abstraction.

Data members – are entities that contain information necessary to represent the class.

Debugging – is the process of identifying and correcting errors which occurs during the compilation of the program.

Dot (.) operator – is a special type of operator which is used to accesses instance members of an object or class members of a class.

Dynamic Binding is the process of linking the function call with the function signature during the execution of the program.

Encapsulation – The binding up of data members and member functions (methods) together into a single unit called class is called Encapsulation.

Escape Sequence – A character preceded by a backslash (\) is an escape sequence and has a special meaning to the compiler, for e.g. The newline character ” \n ” is used within print statements to change line. When an escape sequence is encountered in a print statement, the compiler interprets it accordingly.

Exception Handling-Way of handling anomalous situations during a program-run.

Expression – An expression is a construct made up of variables, operators, and method invocations, which are constructed according to the syntax of the language that evaluates to a single value

Expression – is any valid and legal combination of operators, constants and variables

Fall-through – Missing break statement that leads to fall of control, in which all the cases are executed, irrespective of the switch statement.

final – It is a keyword which when prefixed to a variable makes it a constant.

Formal parameters – are those entities that appear at the point of function declaration or function signature are called Formal parameters.

Function prototype – The first line of a function that consists of access specifier, modifier, return type, function name and list of parameters enclosed within a pair of parenthesis is called function prototype.

Global Variable – variables which is available to entire class (all the methods).

Green – Codename of Java

Identifiers are fundamental building blocks of a program. They are named memory locations or simply names given to variables, objects, classes, functions, arrays etc…

Impure expression – The operands in such an expression are of different datatype

Infinite loop – A loop that never ends.

Infinity – Division by zero or overflow produces infinity. Note that subtracting two infinities produces a NaN. Similarly no exceptions are generated for statements like Math.pow (0, –1) and such statements will result in Infinity as output.

Inheritance – The ability of a class to derive the properties from another class is called Inheritance.

Instance Variables – A global variable defined as non static within the class.

Integral Promotion – Conversion of shorter integral types into bigger integral types.

Interface – is a set of variables and methods like a class.

Iteration statement – Statements that allows a set of instructions to be performed repeatedly.

Java shorthand – A way of combining an arithmetic operator and an assignment operator.

JDK (Java Development Kit) – The JDK is a software development tool used for developing Java applications and applets. It includes the Java Runtime Environment (JRE), an interpreter/loader (JVM), a compiler (JAVAC), an archiver (JAR), a documentation generator (JAVA DOC) and other tools needed in Java development.

Jump Statement – Statement that unconditionally transfers program control within a function.

JVM – Java Virtual Machine, the interpreter of Java that converts Byte code to Object Code

Keywords are the reserved words which convey a special meaning to a language compiler. They can not be used for any other purpose like function name, variable name or object names

L – Value  The memory location of a variable is called L Value (also see R – Value)

Library class – Pre defined classes of java which get included in an application program itself. They are also known as Standard java classes or built-in-java classes, like Math & String

Literal are the fixed values that are assigned to variables which do not change its values during program execution.

Local variable – Variable declared inside a method or block.

Logical Errors – A Logical error is born out of a programmer who misunderstands the logic of the program and writes a syntactically correct code but which does not comply to the algorithm of the problem.

Looping Statement – An Iteration Statement, that executes repeatedly as long as the condition is true

Mark & Sweep – An algorithm that is used to manage garbage collection in Java.

Message passing – is a way of sending / receiving information to / from objects / methods / class.

Modifier – These are keywords which redefines the functionality within the methods. They can be final, native, static, synchronized, transient, volatile etc…

Multilevel Inheritance- A target which inherits a base can be used as a base for another target.

Mutator method – It is a method that sets / changes the value of a data-member of the class, such methods are impure in nature and generally non-return type in nature.

NaN (Not a Number) – No exceptions are generated by floating-point operations. Instead of an interruption in execution, the result of an operation may be positive infinity, negative infinity, or NaN (not a number).

Nested Loop – A loop that contains another loop inside its body.

new-It is a keyword which allocates the memory and instantiates an object.

Non Primitive Data Types: Directly or indirectly dependent on primitive data types. They store the data values with reference to the address or locations. So, they are called as Reference Data Types.  E.g. array, classes, objects, interfaces etc…

Non- Static variables – The instance variables that are accessed by associating them with object separated by a dot.

Normal flow of control – When a command to execute a program is issued, control keeps on moving sequentially from one statement to other from beginning to an end in order to execute them is known as normal flow of control.

Oak – Hypothetical name of Java

Object – An object is an instance of a class, with an identifiable entity having distinct characteristics and behaviour as its blueprint (called Class).

Object Code – The interpreter of Java named JVM (which stands for Java Virtual Machine) then converts the intermediate Byte Code into machine specific executable which runs on the host machine.

Object factory – A producer of objects that accepts some basic information and creates objects on based on this information.

OOP – Object Oriented Programming where equal stress is given to Data as well as procedure / method.

Orphaned Case –  A situation in which arises in the presence of a case statement due to the missing switch statement

Parameter – The variable used with method signature which received value during function call.

Piece-of-code (Variable’s scope)-The program part(s) in which a particular piece-of code or a data value (e.g., variable) can be accessed.

Polymorphism – The ability of a (function) method to behave in more than one form is called polymorphism

POP – Procedure Oriented Programming where the concern is the procedure / process / method but not Data

Precedence – The sequence in which operators are evaluated in a Java expression

Primitive data types – Also called as Basic Data type. They are pre defined or pre built in data types because they are already built in java. E.g.  byte, short, int, long, float, double, char and boolean.

Prototype – A function or a method prototype is the first line of a function that contains information about access specifier, modifier, return type function name and arguments.

Pure expression – All operand in such an expression are of same datatype

R – Value The read value (contents or value) of a variable.

Reader class – is a Character stream classes i.e., it is used to read characters from source.

Record-It is a set of related information.

Reference Data Types – Directly or indirectly dependent on primitive data types. They store the data values with reference to the address or locations. So, they are called as Reference Data Types.  E.g. array, classes, objects, interfaces etc…

Return type – They specify what type of value a function can return, hence they can be of any primitive of reference data types like int, byte, float, char, String or even class types. In case the function doesn’t return any value the keyword ‘void’ is used.

Reusability – The process of adding some additional features to a class without modifying its contents.

Run Time Error – Error occurring during program execution.

Scope – Region within which a variable/ piece-of-code is accessible.

Scope of variable – It is a measure of as to what extent a variable visible and determines the limit within which they can be applied in a program.

Selection Statement – Statement that allows choosing a set-of-Instruction for execution depending upon an expression.

Sequential construct – The Statements in a program are executed sequentially one after the other from to the last statement.

Setter method – It is a method that sets / changes the value of a data-member of the class, such methods are impure in nature and generally non-return type in nature. (also see Mutator)

Source code – The High level language code written by programmers which is not understandable by the computer is known as Source Code. It has an extension of *.java

Statement – Instruction given to the computer to perform any kind of action.

Static initialization – When a variable is initialized with a specific constant before its use in the operation.

static- It is a keyword which in the variable declaration make it class variable. Such variables or methods has only one instance in the physical memory and can be accessed either directly or using the class name. E.g. Math.sqrt( ) where sqrt( ) is a static method of Math class.

String Buffer-It is a type of string class, which allows reasonable space to contain a string in such a way that any change brought affects the same string, thus is a mutable class.

Subscripts – They are cell numbers / index numbers of the array & subscript variable is the variable used along with cell no. E.g., m[4] = 40; where m is subscript variable, [4] is subscript number & 40 is value the stored in the cell.

super –It is a keyword used in inheritance for calling base class constructor. It is also used for calling the base class method in case that method has been overridden.

Syntax Error – Programming language’s grammar rules violation error.

Testing – It is the process of checking program logic manually to ensure whether it contains any error or not.

this – It is a keyword (which is actually a reference) sorting the address of the objects currently invoking a member functions.

throws-It is a keyword used to inform the error handling classes that an error has occurred. It is specified with method prototype.

Token – The smallest individual unit of a Java program

Truncation- Rounding off by removing fractional part or removing parts of a string.

Try and catch- Try contains a block of statements to perform any error occurring within the try block is trapped. Further a report is passed to the exception handler about the error, which is done by the catch block.

Type Promotion-Conversion of all operands up to all the type of the largest operands.

Variable – It is a named memory location which holds a value of a specific datatype.

WORA – Write once run anywhere, term associated with Platform Independence

Wrapper Classes – Wrapper classes wrap the primitive datatypes into respective objects.