Exceptions and Assertions

Author: turingfly

Java-8/src/exceptionsAndAssertions/Assertions.java

@@ -1,33 +1,37 @@
 package exceptionsAndAssertions;
 
 /**
- * 
  * @author chengfeili 
  * Jun 11, 2017 11:25:30 AM
  * 
- *         An assertion is a Boolean expression that you place at a point in
- *         your code where you expect something to be true.
- * 
- *         assert boolean_expression; assert boolean_expression: error_message;
- * 
- *         If assertions are disabled, Java skips the assertion and goes on in
- *         the code. If assertions are enabled and the boolean expression is
- *         true, then our assertion has been validated and nothing happens. The
- *         program continues to execute in its normal manner. If assertions are
- *         enabled and the boolean expression is false, then our assertion is
- *         invalid and a java.lang.AssertionError is thrown.
- * 
- *         1. Internal Invariants You assert that a value is within a certain
- *         constraint. assert x < 0 is an example of an internal invariant. 2.
- *         Class Invariants You assert the validity of an object’s state. Class
- *         invariants are typically private methods within the class that return
- *         a boolean. The upcoming Rectangle class demonstrates a class
- *         invariant. 3. Control Flow Invariants You assert that a line of code
- *         you assume is unreachable is never reached. The upcoming TestSeasons
- *         class demonstrates a control ow invariant. 4. Preconditions You
- *         assert that certain conditions are met before a method is invoked. 5.
- *         Post Conditions You assert that certain conditions are met after a
- *         method executes successfully.
+ * An assertion is a Boolean expression that you place at a point in your code
+ * where you expect something to be true.
+ * 
+ * assert boolean_expression; assert boolean_expression: error_message;
+ * 
+ * If assertions are disabled, Java skips the assertion and goes on in the code.
+ * If assertions are enabled and the boolean expression is true, then our
+ * assertion has been validated and nothing happens. The program continues to
+ * execute in its normal manner. If assertions are enabled and the boolean
+ * expression is false, then our assertion is invalid and a
+ * java.lang.AssertionError is thrown.
+ * 
+ * 1. Internal Invariants. You assert that a value is within a certain
+ * constraint. assert x < 0 is an example of an internal invariant.
+ * 
+ * 2.Class Invariants. You assert the validity of an object’s state. Class
+ * invariants are typically private methods within the class that return a
+ * boolean.
+ * 
+ * 3. Control Flow Invariants. You assert that a line of code you assume is
+ * unreachable is never reached. The upcoming TestSeasons class demonstrates a
+ * control of invariant.
+ * 
+ * 4. Preconditions. You assert that certain conditions are met before a method
+ * is invoked.
+ * 
+ * 5. Post Conditions. You assert that certain conditions are met after a method
+ * executes successfully.
  */
 public class Assertions {
 	public static void main(String[] args) {

Java-8/src/exceptionsAndAssertions/CallingMethodsThatThrowExceptions.java

@@ -1,3 +1,4 @@
+
 package exceptionsAndAssertions;
 
 /**

Java-8/src/exceptionsAndAssertions/ExceptionIntro.java

@@ -13,7 +13,7 @@
  *	2. Checked Exception: includes Exception and all subclasses that 
  *	do not extend RuntimeException.
  *	For checked exceptions, Java requires the code either handle them
- *	ore declare them in the method signature.
+ *	or declare them in the method signature.
  *
  *	3. Error 
  */
@@ -50,8 +50,6 @@ public void TryStatement() {
 	}
 
 	private void getUp() {
-		// TODO Auto-generated method stub
-		
 	}
 
 	public void fall1() {

Java-8/src/exceptionsAndAssertions/TryWithResources.java

@@ -10,24 +10,24 @@
  * 
  * @author chengfeili 
  * Jun 11, 2017 11:21:42 AM
- *
- *         Remember that only a try-with-resources statement is permitted to
- *         omit both the catch and finally blocks. A traditional try statement
- *         must have either or both.
+ * 
+ * Remember that only a try-with-resources statement is permitted to omit both
+ * the catch and finally blocks. A traditional try statement must have either or
+ * both.
  */
 public class TryWithResources {
 	/**
 	 * 
-	 * The new try-with-resources statement automatically closes all
-	 * resources opened in the try clause. This feature is also
-	 * known as automatic resource management, because Java
-	 * automatically takes care of the closing.
-	 *             
-	 * The resources created in the try clause are only in scope within the try block. 
+	 * The new try-with-resources statement automatically closes all resources
+	 * opened in the try clause. This feature is also known as automatic
+	 * resource management, because Java automatically takes care of the
+	 * closing.
+	 * 
+	 * The resources created in the try clause are only in scope within the try
+	 * block.
 	 */
 	public void newApproach(Path path1, Path path2) throws IOException {
-		try (BufferedReader in = Files.newBufferedReader(path1); 
-				BufferedWriter out = Files.newBufferedWriter(path2)) {
+		try (BufferedReader in = Files.newBufferedReader(path1); BufferedWriter out = Files.newBufferedWriter(path2)) {
 			out.write(in.readLine());
 		}
 	}
@@ -41,6 +41,7 @@ public void newApproach(Path path1, Path path2) throws IOException {
  *
  */
 class TurkeyCage implements AutoCloseable {
+	@Override
 	public void close() {
 		System.out.println("Close gate");
 	}
@@ -60,11 +61,13 @@ public static void main(String[] args) {
  *
  */
 class JammedTurkeyCage implements AutoCloseable {
+	@Override
 	public void close() throws IllegalStateException {
 		throw new IllegalStateException("Cage door does not close");
 	}
-	// print 
-	// caught: turkeys ran off 
+
+	// print
+	// caught: turkeys ran off
 	// Cage door does not close
 	public static void main(String[] args) {
 		try (JammedTurkeyCage t = new JammedTurkeyCage()) {
@@ -79,23 +82,19 @@ public static void main(String[] args) {
 
 /**
  * 
- * Resources are closed after the try clause ends and before any catch/finally clauses.
- * Resources are closed in the reverse order from which they were
+ * Resources are closed after the try clause ends and before any catch/finally
+ * clauses. Resources are closed in the reverse order from which they were
  * created.
  *
- * Print: 
- * Close: 2 
- * Close: 1 
- * ex 
- * finally
+ * Print: Close: 2 Close: 1 ex finally
  */
 class Auto implements AutoCloseable {
 	int num;
 
 	Auto(int num) {
 		this.num = num;
 	}
-
+	@Override
 	public void close() {
 		System.out.println("Close: " + num);
 	}