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Control Statements In Java | switch case & for LoopIn general, every program execution can be done from top to bottom in sequential order. But, if we use control statements, then we can change program execution order depending on logic & values. That means, we can skip some lines of code and we can iterate same lines of code based on our requirement. Simply, the control statements in Java are useful to control the program flow. There are different types of control statements in Java such as Selection statements, Iteration statements (Loops) and Jump statements.

There is no limitation for the usage of these control statements in Java. The control statements in Java can be used together or they can be used as nested together with each other. The three classifications of these control statements in Java can used in different situations depending on our requirement. Selection statements are used to execute a block of code only if the condition is true. Iteration statements are used to iterate a block of code repeatedly until the condition is false. And the Jump statements are used to skip the statements and come-out from those.

Java switch case statement is comes under Selection statements. In this Java switch case, it allows a variable to be checked for equality with different types of values. Every variable value is treated as case and the variable can be checked with those values in each case. The following are the important rules of Java switch case statement.

Java switch case variables can only take values as integers, enums and strings.

Java switch case statement can contain any number of cases. Each case must have a value to be checked and executed.

In Java switch case, the value of each case must be match with the variable data type in switch & it must be a literal or a constant.

In Java switch case, if a variable is equals to a case, then the statements under that case will be executed until it reaches the break statement.

If a break statement is executed then the Java switch case terminates the flow and the control come out from that switch statement.

In Java switch case, there is no rule that every case must contain a break statement. If the break doesn't exist then the flow continuesly go through its subsequent cases until the break statement exists.

Java switch case statement may contain a default case which is optional. It must be the last case of the switch. The default case can be executed if all the cases are failed to fulfil the condition. The default case doesn't contain any break statement.

Apart from switch case statements if, nested if, etc are also comes under selection statements which explained below of the page.

A Java for loop is comes under Iteration Statements. In this Java for loop, it allows to iterate a specific block of code multiple times according to our requirement. The syntax of Java for loop is,

for(initialization; condition; increment/decrement) {    //statements }

The flow of control in Java for loop is as follows;

At first the control comes to initialization section in Java for loop. This section is executed only once when the for loop starts its execution. The loop control variables can be declared and initialized in this step. This section ends up with a semi-colon (;) symbol.

Now, the control comes to the condition section. It checks whether the condition is true or not. If the condition is true, then the statements in the Java for loop body can be executed. If the condition is false, then the statements in the Java for loop won't be executed and the control comes out from the for loop; the next line after Java for loop will be executed.

If the condition is true, the list of statements in the for loop block will be executed. After executing all the statements, now the control comes at updating (increment/decrement) section. In this section, we can able to update the loop control variables by incrementing or decrementing them. Semi-colon is not placed at the end of this section because it is the last statement inside the for loop.

Now, again the control comes back to condition section and it checks the condition with modified values. If the condition is true, the Java for loop executes its block of statements and the same process repeats again as explained above. This process continues until the condition is false. After the condition is false the Java for loop terminates and the next statement after for loop will be executed.

Apart from for loop; while loop, do while loop, etc are also comes under Iteration statements which explained below.

There are mainly three jump statements in Java. break, continue and return are the jump statements which explained below.

In this section, we'll go into detail about:

5.1 Control Statements In Java

The control statements in Java, as the name suggests controls the flow of the program. Depending upon the state ( values of variables, user input etc ) the appropriate code is ...Read More

5.2 Selection Statements

5.2.1 Selection Statements In Java

Java supports two selection statements - if and switch. These statements allow us to control the flow of the program. Depending upon the expressions or values, the corresponding...Read More

5.2.2 if Condition In Java

if condition in Java is a conditional branch statement, which can be used to route program execution through different paths. if condition in Java can be used to ...Read More

5.2.3 Nested if Statements In Java

When a if condition is included in the if block of some other if condition then those are called nested ifs in Java. We can have as many nested ifs and it can go into ...Read More

5.2.4 if else if ladder In Java

It is very common in programming to have more than two ways (or branches). e.g., printing the grade of a student like "Distinction", "First Class", "Second Class" and ...Read More

5.2.5 switch Statement In Java

switch provides a better multi-way branch than if-else-if ladder which executes multiple branches depending on the values of an expression. The expression must be of ...Read More

5.2.6 if else Vs switch Performance In Java

Although if-else and switch are multi-way branch statements, they are not completely same. switch can be used only for a specific value and can not be used for ...Read More

5.2.7 Nested switch Statements In Java

Similar to if statement, switch statements can be nested as well. In nested switch statements, switch statements can be presented with in the switch statements. In order to...Read More

5.2.8 Fall Through Switch Case Statements In Java

It is not necessary for every case in the switch Statement In Java to have a break. Some times we might have a situation where we have the same or similar handling ...Read More

5.3 Blocks of code

5.3.1 Block Of Code In Java

Block of code in Java allows grouping of two or more statements. We use curly braces { } to denote a block of code in Java. Block of code in Java can be used where ever we...Read More

5.3.2 Scope Of Variables In Nested/Multiple Blocks

Scope Of Variables in Nested/Multiple Blocks in Java States that variables declared in outer blocks will be accessible in inner blocks, where as variables declared in ...Read More

5.3.3 Lifetime Of Variable In Java

Lifetime of a variable in Java defines how long a variable and its value are valid. The life time of a variable can be depend on the declaration of that variable. If it is declared at...Read More

5.3.4 Expressions, Statement, Line & Block In Java

Although the terms expression, statement, line, block, condition, and body represent code (or program), there are small differences between them. It is required to ...Read More

5.4 Iteration statements (Loops)

5.4.1 Iteration Statements Or Loops In Java

Java's Iteration statements are for, while and do-while. These statements are commonly called as loops. A loop repeatedly executes the same set of instructions until a ...Read More

5.4.2 while Loop In Java

The while loop is Java’s most fundamental looping statement. It repeats statement or block while its controlling expression (termination condition) is true. The while ...Read More

5.4.3 for Loop In Java

The for statement in Java provides a compact way to iterate over a range of values. We often call it as the "for loop" because of the way in which it repeatedly loops as long ...Read More

5.4.4 for Vs while Loop In Java

Although for and while are both loops, there are few differences in the syntax and the usage. for loop is used when we know the number of iterations we have to perform i.e....Read More

5.4.5 do while Loop In Java

do-while loop is similar to while loop statement but do-while loop executes all the statements in the block, at least once and then checks the condition at the end. If the condition...Read More

5.4.6 Nested Loops in Java

Nested loops are very common in programming, when we have to call a loop multiple times. For e.g., printing 1 2 3 4 5, can be done using a loop, but for printing it four ...Read More

5.4.7 Nested While Loop In Java

Placing one while loop with in the body of another while is called Nested while loop in java programm. Similar to nested loop. Nesting while, do-while will work similar to ...Read More

5.4.8 Nested for Loop In Java

Placing one for loop with in the body of another for is called nested for loop. This kind of nesting is commonly used in programming. Having loops inside loops, which are ...Read More

5.4.9 for Loop Example Program In Java - Sum Of Numbers

This example finds the sum of all numbers till a given input number using for Loop In Java. e.g., if the input is 6, then the sum is 1 + 2 + 3 + 4 + 5 + 6 = 21; So, it sequentially add ...Read More

5.4.10 Factorial Program In Java Using for Loop

This program calculates the factorial of the given number using for Loop In Java. The program finds the factorial of the given number 6, by multiplying the variable factorial with...Read More

5.4.11 Factorial Program In Java Using While Loop

This is Java Program " Factorial Using While Loop". The Java Program shows how to Calculate The factorial of a given number using while Loop. It finds the factorial of the ...Read More

5.5 Jump Statements

5.5.1 Jump Statements In Java

Java supports three jump statements: break, continue, and return. These statements transfer control to another part of your program. These statements can be used inside...Read More

5.5.2 Using Break In for Loop To Exit

By using break, you can force immediate termination of a loop even though there are iterations to be completed. e.g., In the following program which prints numbers from 1 to...Read More

5.5.3 Using break in switch case Statement

break can be used to come out of the switch statement. It is compulsory to put a break statement after each case block, then only we can stop the execution. If there is no break it...Read More

5.5.4 Using Java Break Statements as Java Goto

Java does not support goto to avoid complex code. When we use lots of goto's it will be very difficult to understand that code. break when used with label's can be a substitute for...Read More

5.5.5 Using break In Nested Loop Java Program

We can also use breaks in nested loop programs. Here is the example of using break statement in nested loops. The loops are for loops. If we put break in inner loop then it will...Read More

5.5.6 Java continue Statement

continue stops a particular iteration in a loop. e.g., If a loop has 15 iterations and having 5 lines of code, if in iteration 10 the continue statement is encountered at line 3, then...Read More

5.5.7 Java return Statement

return statement is used to explicitly return from a method. It causes the program control to transfer back to the caller of the method. return can be used to return from...Read More

5.6 Java for loops vs Java while loops vs Java do while loops

Java Operators | Ternary Operator

Java Operators

are symbols those are useful to perform certain operations. In other words, Java Operators are objects that perform specific actions on particular values and find the result. They help in performing operations. There are different types of Java operators like Java ternary operator, arithmetic operator, Increment and Decrement operator, Modulus operator, boolean logical operator, relational operator, Short circuit logical operator, assignment operator and bitwise operator. All these classifications of Java operators can be used in different types of operations.

For example take the expression, 24+14*50. Where +, * are the Java operators and 24, 14, 50 are the operands in Java. According to the operation, the no.of operands will be vary for every Java operator. There are two operands for addition operator and there is only one operand for unary operator; but for Java ternary operator, there are three operands. In Java operators, ternary operator is the only operator which contains three operands.

Java ternary operator is also known as Conditional Operator. This Java ternary operator is useful for evaluating boolean expressions. The main purpose of this ternary operator is to determine which value should be assign to the variable. Java ternary operator uses the symbol '? :'. It completely works like a if-else statement. Boolean expression is the first operand in this ternary operator. If the condition is true then second operand value will be assigned to the variable otherwise the third operand value will be assigned. So, Java ternary operator is useful for replacing if_then_else statements.

In this chapter, we can also learn about Arithmetic operator, Increment and Decrement operator, Modulus operator, Boolean logical operator, Relational operator, Short circuit logical operator, Assignment operator, Operator Precedence And Associativity in detail at below.

In this Java Operators section, we'll go into detail about:

4.1 Operators In Java

Java Operators are special symbols that perform specific operations on operands and find the result. e.g., +, -, *, >, <=, !. These Java operators help in performing operations like ...Read More

4.2 Java Arithmetic Operators

Arithmetic Operators help in performing the algebra operations like addition, subtraction, multiplication and division. The list of all supported Arithmetic Operators In Java are...Read More

4.3 Basic Arithmetic Operators In Java

Basic Arithmetic Operators are sub group of Java Arithmetic Operators which include only addition, subtraction, multiplication and division. Here you have Basic Arithmetic ...Read More

4.4 Increment And Decrement Operators In Java

Increment Operator increases its operand by 1. The Decrement Operator decreases its operand by 1. Instead of x = x + 1; we could do x++; Increment And Decrement ...Read More

4.5 Modulus Operator In Java

Java has one important arithmetical operator you may not be familiar with, %, also known as the modulus operator.The modulus operator, % returns the remainder of a ...Read More

4.6 Arithmetic Compound Assignment Operators In Java

Arithmetic Compound Assignment Operators In Java are used to combine an arithmetic operation with an assignment operation. e.g., marks += 5; instead of marks = ...Read More

4.7 Relational Operators In Java

The relational operators determine the relationship between two operands. e.g., 3 is greater than 2, 25 is less than 30. The following six relational operators are supported ...Read More

4.8 Boolean Logical Operators In Java

Boolean logical operators operate only on boolean operands. These operators combine one or two boolean values to form a new boolean depending upon the operation. Logical...Read More

4.9 Short Circuit Logical Operators In Java

Java provides two boolean operators boolean AND and boolean OR which are not provided by the other language and these operators are known as Short-Circuit logical ...Read More

4.10 Assignment Operator In Java

Assignment operator is used to assign a value of an expression to a variable. Usual assignment operator we see is ' = '. e.g., a = 5;. Like other languages Java also uses assignment ...Read More

4.11 Java Ternary Operator

Java Ternary operator can be used to replace certain types of if-then-else statements. It is called Java ternary operator because it uses three operands. The syntax for Java ternary operator...Read More

4.12 Java Operator Precedence And Associativity

Operator precedence plays an important role if there are multiple operators involved in an expression. E.g., int a = 7 * 3 + 24 / 3 - 5; In java * and / have more precedence compared to...Read More

4.13 Temperature Conversion Program In Java

Java Variables | Types of Variables In Java (Local Variable, Instance Variable, Static Variable)

Java Variables are memory pieces those can contain values of data. In Java variables, every variable has its data type, which represents variable's memory size and layout; the operations those can be applicable to the Java variables. Java variables are commonly used for storing the information which Java program needs. The information can be of any type codes, texts, numbers, etc.

In Java variables, every variable must be declared before it can be used. The declaration of Java Variables is as : data type variable1 [ = value][, variable2 [= value][, ...] ; There are mainly three types of variables in Java. All these types of variables can be differ by their declaration. The following are the different types of variables which we going to discuss. (a) Local variable (b) Instance variable (c) Static variable

Local variable can be declared in methods, blocks or constructors. This type of variables can be destroyed once it come out from the method, block or constructor. In the three types of variables, local variables can't have default values. So, local variables must be declared and assigned some values before using them.

Instance variable can be declared with in a class and outside of method, block or constructor. A slot is created for each instance variable value, when a space for an object is allocated in the heap. Instance variable can be created when ever an object is created by using the keyword 'new' and it can destroy if the object is destroyed. Instance Variable can take access modifiers. Instance variables can directly accessed, by calling name of the variable with in the class.

Static variable can also be called as Class variable. The static variable can be declared with the keyword static and this static variable can be declared with in a class and outside of method, block or constructor. In all three types of variables, static variable can occasionally used rather than declared as constants. Static memory is used for storing static variable. Static variable is rarely used apart from declaring final and use as either private or public constants. We can access the static variable by calling with the class name as ClassName.VariableName. Static variable can be created at the program begins and destroyed at the program ends.

Apart from these, this chapter also include the topics like Type Conversion and Type Casting which explained deeply at below.

In this Java Variables section, we'll go into detail about:

3.1 Java Variables

Java Variables can be used to store information/data. Once a variable is declared, it can be initialized with some value and later can be changed to some other value. A variable can ...Read More

3.2 Scope Of Variables In Same Block

Scope of variable is nothing but the statements or expressions in which the variable can be used. Any variable is in scope ( valid ) in the statements below its ...Read More

3.3 Type Conversion In Java

Sometimes it is necessary to convert variables of one type to another type. e.g., convert values present in an int to byte or from short to long. Type conversion happens between ...Read More

3.4 Type Casting In Java

2. Data Types

Java Data Types | Java Literals:

Data type

is a special type of keyword which is useful for allocating sufficient memory for that data. In other words, Java Data Types are the classification, to identifying one of various types of data such as real number, integer, floating point or boolean. That determines the possible values for that particular type and the operations that can be done on values of that type.

So, Java data types are in various forms to store the different types of information. These Java data types are mainly classified into 2 types. (a) Primitive Data Types and (b) Non-Primitive Data Types . Java data types can not be modified once they declared.

The primitive data types in Java are also called as Fundamental data types or Basic data types. In primitive, Java data types are mainly classified into four types. They are Integer Data Types In Java, Floating-Point Data Types In Java, Character Data Types in Java and Boolean Data Types in Java. In Non-Primitive, Java data types are further classified into three types. User defined data type is one of these Non-primitive Java data types.

According to the requirement we can choose the appropriate type in Java data types.

Java integer data types are broadly classified into four types depending on their size. They are byte, short, int and long. In Java integer data type, the allowed size is calculated depending on number of bytes. The Java integer also contains negative numbers. So, this is the reason, the size is ranging from -128 to +127 in Java integer. Java long has the size of 64 bits or 8 bytes. Distance to sun in kilo meters, hair count, mobile number are the examples come under Java long.

The topics that we fully cover in this section are Data Types, Primitive Data Types, Integer Data Types, Floating Point Data Types, Java Character, Literals, Integer Literals, Floating Point Literals, etc which deeply explained below.

In this Java data types section we discuss in detail about :

2.1 Data Types In Java

Java is a strongly typed language, which means every data or information has a type Known To Be "Data Type"and that Data Type can not be changed once declared. So every ...Read More

2.2 Primitive Data Types

2.2.1 Primitive Data Types In Java

Primitive data types are basic data types supported by Java which can be used to store the information. These data types can be further combined to make more ...Read More

2.2.2 Integer Data Types In Java

The Java integer data types are used to store whole numbers like 2, 3, 267, -1245, 0, 8382923 etc. Integers do not contain decimal points, so 3.14 and 4221.76 are not ...Read More

2.2.3 Floating Point Data Types In Java

The floating-point data types are used to store decimal numbers like 3.45, -1267.89, 0.33424324, 0.00011, 4.0, 189.0 etc. Java supports two floating point types ...Read More

2.2.4 Java Character

A character type (typically called "char") may contain a single letter, digit, punctuation mark, symbol, formatting code, control code, or some other specialized ...Read More

2.2.5 Boolean Data Types In Java

Boolean is the primitive data type in Java. There are only two values that a boolean type can take they are: true or false. Boolean type is used when we want to ...Read More

2.2.6 Literals

2.2.6.1 Java Literals

A constant value in a program is denoted as literal. e.g., 10, 534, 29.5, 'c', true, false, 'E', '&' are all literals of various datatypes. e.g., int num = 10; In the statement 10 is ...Read More

2.2.6.2 Integer Literals In Java

Integer literals are used to initialize integer group datatypes like byte, short, int and long. These literals are nothing but a sequence of digits. If they are suffixed with ...Read More

2.2.6.3 Floating Point Literals In Java

Floating Point Literals In Java contains the fractional parts. e.g., 251.73, 3.14, 98766.12, 10E+03, 2.78e-7. If the Floating Point Literal is suffixed with letter F or f, then it is ...Read More

2.2.6.4 Character Literals In Java

Character Literals In Java are used for primitive data type char. Character Literals Are included in a single quotation ('ex') marks. Java Character Literals are 16-bit ...Read More

2.2.6.5 String Literal In Java

String Literals In Java is a sequence of characters which has to be included between double quotes ("ex") and should occur on a single line. String Literals Double Quotes ...Read More

2.2.6.6 Boolean Literals In Java

How To Learn Java Programming Language?

Java Programming language

is currently one of the world's most significant and popularly used computer languages, and it (Java Programming) has held this uniqueness for many years. Unlike some other computer languages whose influence has loosened for the time being, while Java's has grown. And most of the people still learn Java instead of other programming languages because of its popularity.

As of 2016, Java programming language is one of the most popular programming languages in use, particularly for client-server web-applications, with a reported 9 million developers using and working on it.

Java Programming Language was developed by James Gosling, Chris Warth, Patrick Naughton, Mike Sheridan and Ed Frank at Sun Microsystems, Inc in the year 1991. At first Java Programming Language was named as Oak, later that it was renamed to Java in the year 1995.

Java Programming is a platform independent language. The Internet (World Wide Web) made Java programming more valuable. Since, Internet is connected to different types of systems which having different CPU's & environments, it must have the programs to run on any OS, CPU and Platform. Since, Java programming obtain platform independence and can able to run on any platform like Unix, Intel, Mac etc., it was widely used. Java language also protects two other major issues of Internet, they are security & portability.

In this section, we'll go into detail about Java basics:

1.1 What Is Programming ? Why We Need Programming

The Computer Programming help in automating the tasks which are time consuming, error prone, repetitive, not person dependent etc., They also ...Read More

1.2 How To Learn Programming & Programming Skills

As computer programmers or would-be programmers, it is really important to learn the programming skills along with languages. When we have strong ...Read More

1.3 How Can I Be A Good/Excellent Programmer

Learning a computer programming language is very easy compared to writing good programs and using the language effectively. For a beginner, it might take...Read More

1.4 More Details On Java

1.4.1 Creation Of Java Language for Platform Independence - WORA

Java's primary motivation was platform independence and not internet. Platform independence means the ability to write a program on one platform and...Read More

1.4.2 Java And Internet - Creating Java Applet

Internet helped Java to bring it to the forefront and Java language influenced Internet by simplifying the web programming and inventing applets. Applets expanded the...Read More

1.4.3 What Is Servlet In Java Language

Java language also has Servlets which are useful in dynamically extending the functionality of web browser. With Servlets, Java spanned on the both sides of ...Read More

1.4.4 Java Bytecode

Java in order to support security and portability, does not compile the source code to executable code. It is translated into bytecode, which is highly optimized set of ...Read More

1.4.5 Java 8 Features Java Buzzwords

There are few other features of Java language apart from Applets, Security, Portability and Servlets which are also important. These are also called as Java Buzzwords. Which are ...Read More

1.4.6 JDK, JRE, JVM, JIT, Java Compiler

Here we will discuss about various terms like JDK, JRE, JVM, JIT and applications like javac, java. Java is distributed in two packages - JDK and JRE. When JDK is ...Read More

1.4.7 Java versions and changes done in every version

Although initial version of Java language, the 1.0 by itself extraordinary, the latter changes to Java were equally important and have highly evolved over ...Read More

1.4.8 Java Keywords

There are 50 keywords in java language which have special meaning. These will be used to communicate with the compiler. You cannot use any of the following keywords as ...Read More

1.5 Simple Programs and Development environment

1.5.1 Installation Of Java on your PC

Here we will discuss how to install Java on a Windows 7 64-bit machine. The steps are not exactly same but more or less same for any other Windows version or ...Read More

1.5.2 Java Sample Program - Simple 'Hello World' Program In Java Language

Lets look at the simplest Java language program which prints Hello World onto the output screen. Every Java program needs this structure and with out this the program ...Read More

1.5.3 How to Compile and Run Java Program In Cmd Prompt