Exception Handling Code snipppets

Author: sathishmepco

ExceptionHandling/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.7"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

ExceptionHandling/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>ExceptionHandling</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

ExceptionHandling/.settings/org.eclipse.jdt.core.prefs

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+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.7
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=1.7
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.source=1.7

ExceptionHandling/bin/com/cdac/CheckedExceptions.class

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+package com.cdac;
+
+import java.io.FileReader;
+
+public class CheckedExceptions {
+	
+	public static void main(String[] args) {
+		//this exception checked at compile time
+		//handle this with try catch to compile the program
+		FileReader filereader = new FileReader("FilePath");
+		
+		
+		
+	}
+
+}

ExceptionHandling/bin/com/cdac/UnCheckedExceptions.class

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+package com.cdac;
+
+public class UnCheckedExceptions {
+	
+	public static void main(String[] args) {
+		numberFormatException();
+		divideByZero();
+		nullPointerException();
+		stringIndexOutOfBoundException();
+		classCastException();
+	}
+	
+	public static void numberFormatException(){
+		String str = "ten";
+		
+		//this code will throw NumberFormatException
+		//this is runtime exception
+		//this exception checked at runtime only
+		//use try catch to handle this exception
+		int i = Integer.parseInt(str);
+	}
+	
+	public static void divideByZero(){
+		//the below code will throw ArithmeticException
+		//divide by 0 error
+		//use try catch to handle this exception
+		int a = 10/0;
+	}
+	
+	public static void nullPointerException(){
+		String firstName = null;
+		int length = firstName.length();
+		System.out.println("Length of the first name is : "+length);
+	}
+	
+	public static void stringIndexOutOfBoundException(){
+		String name = "Core Java";
+		char charAtIndex100 = name.charAt(100);
+		System.out.println("Char at index 100 is : "+charAtIndex100);
+	}
+
+	public static void classCastException(){
+		Object o = new Integer(10);
+		String sObj = (String) o;
+		System.out.println(sObj);
+	}
+
+}

ExceptionHandling/bin/com/cdac/customexception/Student.class

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+package com.cdac.customexception;
+
+public class Student implements Comparable<Student>{
+	
+	private int rollNo;
+	private String name;
+	
+	public Student(){
+		rollNo = -1;
+		name = "";
+	}
+
+	public Student(int rollNo, String name) {
+		super();
+		this.rollNo = rollNo;
+		this.name = name;
+	}
+
+	public int getRollNo() {
+		return rollNo;
+	}
+
+	public void setRollNo(int rollNo) {
+		this.rollNo = rollNo;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+	
+	@Override
+	public String toString() {
+		return rollNo+" "+name;
+	}
+
+	@Override
+	public int compareTo(Student o) {
+		return this.rollNo - o.rollNo;
+		
+		//DECREASING ORDER BY ROLL NO
+//		return o.rollNo - this.rollNo ;
+	}
+}

ExceptionHandling/bin/com/cdac/customexception/StudentDB.class

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+package com.cdac.customexception;
+
+public class StudentDB {
+Student[] students;
+	
+	public StudentDB() {
+		students = new Student[3];
+		Student s1 = new Student(1,"Name1");
+		Student s2 = new Student(2,"Name2");
+		Student s3 = new Student(3,"Name3");
+		students[0] = s1;
+		students[1] = s2;
+		students[2] = s3;
+	}
+	
+	public Student getStudent(int rollNo) throws StudentNotFoundException{
+		for(int i=0;i<students.length;i++)
+			if(rollNo == students[i].getRollNo())
+				return students[i];
+		throw new StudentNotFoundException("Student Record not found");
+	}
+
+}

ExceptionHandling/bin/com/cdac/customexception/StudentMain.class

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+package com.cdac.customexception;
+
+public class StudentMain {
+	
+	public static void main(String[] args) {
+		StudentDB database = new StudentDB();
+		try {
+			//there is no record for rollno 6
+			//so the code will throw exception
+			Student s = database.getStudent(6);
+			System.out.println("Student name is :"+s.getName());
+		} catch (StudentNotFoundException e) {
+			System.out.println(e.getMessage());
+		}
+	}
+}

ExceptionHandling/bin/com/cdac/customexception/StudentNotFoundException.class

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+package com.cdac.customexception;
+
+public class StudentNotFoundException extends Exception{
+	public StudentNotFoundException(String message){
+		super(message);
+	}
+}

ExceptionHandling/bin/com/cdac/errors/OutOfMemoryError.class

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+package com.cdac.errors;
+
+public class OutOfMemoryError {
+	public static void main(String[] args) {
+		//this code will throw OutOfMemoryError
+		//VM does not have enough space to create the objects
+		Integer intArray[] = new Integer[Integer.MAX_VALUE];
+	}
+}

ExceptionHandling/bin/com/cdac/errors/StackOverflowError.class

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+package com.cdac.errors;
+
+public class StackOverflowError {
+	
+	public static void main(String[] args) {
+		//this code will produce stackoverflow error
+		//calling main method inside main method
+		main(args);
+		
+		//calling any method without any base condition 
+		//will lead to stack overflow error
+	}
+
+}