Added java/collections and java/error handling sample code

10 files changed, 213 insertions, 0 deletions

diff --git a/java/12-error-handling-2/.gitignore b/java/12-error-handling-2/.gitignore
new file mode 100644
index 0000000..e493dd6
--- /dev/null
+++ b/java/12-error-handling-2/.gitignore
@@ -0,0 +1,2 @@
+bin
+dist
diff --git a/java/12-error-handling-2/Maths.java b/java/12-error-handling-2/Maths.java
new file mode 100644
index 0000000..b61a9f2
--- /dev/null
+++ b/java/12-error-handling-2/Maths.java
@@ -0,0 +1,11 @@
+public class Maths {
+	
+	public int factorial(int number) throws MathsException {
+		if (number < 0) {
+			MathsException e = new MathsException("Factorial of " + number + " not defined");
+//			e.setX(100);
+			throw e;
+		}
+		return number == 0 ? 1 : number * factorial(number - 1); 
+	}
+}
diff --git a/java/12-error-handling-2/MathsException.java b/java/12-error-handling-2/MathsException.java
new file mode 100644
index 0000000..bdbaf81
--- /dev/null
+++ b/java/12-error-handling-2/MathsException.java
@@ -0,0 +1,22 @@
+public class MathsException extends Exception {
+
+	public MathsException() {
+		// TODO Auto-generated constructor stub
+	}
+
+	public MathsException(String message) {
+		super(message);
+		// TODO Auto-generated constructor stub
+	}
+
+	public MathsException(Throwable cause) {
+		super(cause);
+		// TODO Auto-generated constructor stub
+	}
+
+	public MathsException(String message, Throwable cause) {
+		super(message, cause);
+		// TODO Auto-generated constructor stub
+	}
+
+}
diff --git a/java/12-error-handling-2/MathsTest.java b/java/12-error-handling-2/MathsTest.java
new file mode 100644
index 0000000..7b6827c
--- /dev/null
+++ b/java/12-error-handling-2/MathsTest.java
@@ -0,0 +1,32 @@
+public class MathsTest {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		Maths m = new Maths();
+		int result = 0;
+		
+		try {
+			m.factorial(-5);
+			m.factorial(5); // Not executed
+		} catch (MathsException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+		
+		try {
+		    result = m.factorial(-5);
+		    // ...
+		} catch(MathsException me) {
+//			System.err.println(me.getX());
+			System.err.println("Factorial method failed");
+		} finally {
+			System.out.println("Inside finally block");
+		}
+		
+		System.out.println(result);
+		
+	}
+
+}
diff --git a/java/12-error-handling-2/MathsTest2.java b/java/12-error-handling-2/MathsTest2.java
new file mode 100644
index 0000000..4aa8b59
--- /dev/null
+++ b/java/12-error-handling-2/MathsTest2.java
@@ -0,0 +1,27 @@
+public class MathsTest2 {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		Maths m = new Maths();
+		int result = 0;
+		
+		try {
+		    result = m.factorial(-5);
+		} catch(MathsException me) { // Catching a specific exception
+			System.err.println("Caught a MathsException");
+		} catch(Exception e) { // Catching the super type
+			System.err.println("Caught an Exception");
+		}
+		
+		try {
+			result = m.factorial(-5);
+		} catch (MathsException | ArrayIndexOutOfBoundsException e) { // Java SE 7
+			
+		}
+		
+		System.out.println(result);
+	}
+
+}
diff --git a/java/12-error-handling-2/MathsTest3.java b/java/12-error-handling-2/MathsTest3.java
new file mode 100644
index 0000000..ca45e5c
--- /dev/null
+++ b/java/12-error-handling-2/MathsTest3.java
@@ -0,0 +1,21 @@
+public class MathsTest3 {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		Maths m = new Maths();
+		int result = 0;
+		
+		try {
+		    result = m.factorial(-5);
+		} catch(MathsException e) {
+			System.err.println("Factorial method failed");
+			System.err.println(e.getMessage());
+			e.printStackTrace();
+		}
+		
+		System.out.println(result);
+	}
+
+}
diff --git a/java/12-error-handling-2/MathsTest4.java b/java/12-error-handling-2/MathsTest4.java
new file mode 100644
index 0000000..b5cca8a
--- /dev/null
+++ b/java/12-error-handling-2/MathsTest4.java
@@ -0,0 +1,33 @@
+public class MathsTest4 {
+
+	/**
+	 * @param args
+	 * @throws MathsException 
+	 */
+	public static void main(String[] args) throws MathsException {
+		Maths m = new Maths();
+		int result = 0;
+		
+		// No catching! Then the method should be declared
+		// to throw the exception (or a super type like
+		// Exception or even Throwable)
+		
+//		m.factorial(5);
+		
+		// Look! A try block can be defined without a catch block
+		// as well.
+		try {
+		    result = m.factorial(-5);
+		    System.out.println("xxx");
+		} finally {
+			System.out.println("Inside finally block");
+		}
+		
+		// No try block is also possible
+		// Since the method is declared to duct the exception
+		result = m.factorial(-5);
+		
+		System.out.println(result);
+	}
+
+}
diff --git a/java/12-error-handling-2/MathsTest5.java b/java/12-error-handling-2/MathsTest5.java
new file mode 100644
index 0000000..56bf64d
--- /dev/null
+++ b/java/12-error-handling-2/MathsTest5.java
@@ -0,0 +1,21 @@
+public class MathsTest5 {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) throws Exception {
+		Maths m = new Maths();
+		int result = 0;
+		
+		try {
+		    result = m.factorial(-5);
+		} catch (MathsException me) {
+			throw new Exception("My exception wrapper", me);
+		} finally {
+			System.out.println("Inside finally block");
+		}
+		
+		System.out.println(result);
+	}
+
+}
diff --git a/java/12-error-handling-2/MathsTest6.java b/java/12-error-handling-2/MathsTest6.java
new file mode 100644
index 0000000..7f176aa
--- /dev/null
+++ b/java/12-error-handling-2/MathsTest6.java
@@ -0,0 +1,22 @@
+public class MathsTest6 {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		Maths m = new Maths();
+		int result = 0;
+		
+		try {
+		    result = m.factorial(-5);
+		} catch(MathsException me) {
+			System.err.println("Factorial method failed");
+			System.exit(1);
+		} finally {
+			System.out.println("Inside finally block");
+		}
+		
+		System.out.println(result);
+	}
+
+}
diff --git a/java/12-error-handling-2/MathsTest7.java b/java/12-error-handling-2/MathsTest7.java
new file mode 100644
index 0000000..f55cfad
--- /dev/null
+++ b/java/12-error-handling-2/MathsTest7.java
@@ -0,0 +1,22 @@
+public class MathsTest7 {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		Maths m = new Maths();
+		int result = 0;
+		
+		try {
+		    result = m.factorial(-5);
+		} catch(MathsException me) {
+			System.err.println("Factorial method failed");
+			return;
+		} finally {
+			System.out.println("Inside finally block");
+		}
+		
+		System.out.println(result);
+	}
+
+}