| Types java app |
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| Data Types and Operators |
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| (Primitive Data Types) |
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| (Non-Primitive Data Types) |
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| Control Flow Statements |
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| Conditional Statements |
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| Looping Statements |
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| Branching Statements |
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| Object-Oriented Programming (OOP) |
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| Classes and Objects |
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| Inheritance |
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| Polymorphism |
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| Encapsulation |
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| Abstraction |
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| Exception Handling |
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| Introduction to Exceptions |
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| Collections Framework |
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| Overview of Collections |
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| Commonly Used Collections |
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| Iterators |
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| Java I/O |
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| File Handling |
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| Serialization |
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| Multithreading |
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| Introduction to Threads |
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| Thread Synchronization |
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| GUI Programming with Swing |
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| Introduction to Swing |
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| Event Handling |
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| Advanced Topics |
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| Java Database Connectivity (JDBC) |
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| JAVA CODE |
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Java Basics
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Working with Objects
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Arrays, Conditionals, and Loops
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Creating Classes and Applications in Java
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More About Methods
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Java Applet Basics
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Graphics, Fonts, and Color
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Simple Animation and Threads
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More Animation, Images, and Sound
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Managing Simple Events and Interactivity
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Creating User Interfaces with the awt
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Windows, Networking, and Other Tidbits
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Modifiers, Access Control, and Class Design
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Packages and Interfaces
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Exceptions
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Multithreading
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Streams and I/O
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Using Native Methods and Libraries
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Under the Hood
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Java Programming Tools
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Working with Data Structures in Java
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Advanced Animation and Media
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Fun with Image Filters
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Client/Server Networking in Java
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Emerging Technologies
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appendix A :- Language Summary
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appendix B :- Class Hierarchy Diagrams
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appendix C The Java Class Library
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appendix D Bytecodes Reference
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appendix E java.applet Package Reference
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appendix F java.awt Package Reference
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appendix G java.awt.image Package Reference
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appendix H java.awt.peer Package Reference
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appendix I java.io Package Reference
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appendix J java.lang Package Reference
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appendix K java.net Package Reference
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appendix L java.util Package Reference
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In Java, logical operators are used to perform logical operations on boolean expressions. They are fundamental in controlling the flow of execution in programs through conditional statements like ‘if‘, ‘while‘, and ‘for‘ loops. Java provides several logical operators, each serving a specific purpose. Let’s dive into the details of each logical operator:
1. Logical AND (&&)
The logical AND operator is a binary operator that returns ‘true‘ only if both operands are ‘true‘. It is commonly used in conditional statements to ensure that multiple conditions are met.
Syntax:
boolean result = expression1 && expression2;
Example:
boolean a = true;
boolean b = false;
boolean c = true;
boolean result = a && b; // result is false because b is false
boolean result2 = a && c; // result2 is true because both a and c are true
2. Logical OR (||)
The logical OR operator is also a binary operator that returns ‘true‘ if at least one of the operands is ‘true‘. It is used when any one of multiple conditions being true is acceptable
Syntax:
boolean result = expression1 || expression2;
Example:
boolean a = true;
boolean b = false;
boolean result = a || b; // result is true because a is true
boolean result2 = b || false; // result2 is false because both b and the other operand are false
3. Logical NOT (!)
The logical NOT operator is a unary operator that returns the opposite of the boolean value it operates on. If the operand is ‘true‘, it returns ‘false‘, and vice versa.
Syntax:
boolean result = !expression;
Example:
boolean a = true;
boolean result = !a; // result is false because a is true
boolean b = false;
boolean result2 = !b; // result2 is true because b is false
4. Logical XOR (^)
The logical XOR (exclusive OR) operator returns ‘true‘ if exactly one of the operands is ‘true‘, but not both. It is less commonly used compared to AND and OR.
Syntax:
boolean result = expression1 ^ expression2;
Example:
boolean a = true;
boolean b = false;
boolean result = a ^ b; // result is true because one operand is true and the other is false
boolean result2 = a ^ true; // result2 is false because both operands are true
Short-Circuiting in Logical Operators
Short-Circuit AND (&&)
The ‘&&‘ operator is a short-circuit operator. This means that if the first operand evaluates to ‘false‘, the second operand is not evaluated because the result will definitely be ‘false‘.
Example:
boolean a = false;
boolean b = true;
boolean result = a && b; // result is false, b is not evaluated
Short-Circuit OR (||)
The ‘||‘ operator is also a short-circuit operator. If the first operand evaluates to true, the second operand is not evaluated because the result will definitely be true.
Example:
boolean a = true;
boolean b = false;
boolean result = a || b; // result is true, b is not evaluated
Truth Tables
Understanding the behavior of logical operators can be further simplified with truth tables.
AND (&&)
| A | B | A && B |
|---|---|---|
| true | true | true |
| true | false | false |
| false | true | false |
| false | false | false |
OR (||)
| A | B | A || B |
|——-|——-|——–|
| true | true | true |
| true | false | true |
| false | true | true |
| false | false | false |
NOT (!)
| A | !A |
|---|---|
| true | false |
| false | true |
XOR (^)
| A | B | A ^ B |
|---|---|---|
| true | true | false |
| true | false | true |
| false | true | true |
| false | false | false |
Combining Logical Operators
Logical operators can be combined to form complex conditions.
Example:
boolean a = true;
boolean b = false;
boolean c = true;
boolean result = (a && b) || (c && !b); // result is true
In this example, ‘(a && b)‘ evaluates to ‘false‘, and ‘(c && !b)‘ evaluates to true. Therefore, ‘false || true‘ results in ‘true‘.
Practical Use Cases
Logical operators are widely used in control flow statements.
Example in an if statement:
int age = 25;
boolean hasLicense = true;
if (age >= 18 && hasLicense) {
System.out.println("You can drive.");
} else {
System.out.println("You cannot drive.");
}
Example in a while loop:
int counter = 0;
while (counter < 10 && counter != 5) {
System.out.println("Counter: " + counter);
counter++;
}
In this example, the loop will continue until ‘counter‘ is less than 10 and not equal to 5.
Understanding these logical operators and how they work is crucial for making effective decisions in your Java programs. They allow you to create complex logical conditions and control the flow of your program precisely.
