Finalize and String programs

Author: akash-coded

EqualsImplementation.java

@@ -0,0 +1,23 @@
+public class EqualsImplementation {
+    public boolean equals(Object anObject) {
+        if (this == anObject) {
+            return true;
+        }
+        if (anObject instanceof String) {
+            String anotherString = (String) anObject;
+            int n = value.length;
+            if (n == anotherString.value.length) {
+                char v1[] = value;
+                char v2[] = anotherString.value;
+                int i = 0;
+                while (n-- != 0) {
+                    if (v1[i] != v2[i])
+                        return false;
+                    i++;
+                }
+                return true;
+            }
+        }
+        return false;
+    }
+}

FinalizeMethod.java

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+class FinalizeMethod {
+    public static void main(String[] args) throws Throwable {
+        FinalizeMethod obj = new FinalizeMethod(); // 1st object
+        obj = null;
+        // obj.finalize(); // Uncaught checked exception
+        // obj = new FinalizeMethod(); // 1st object becomes orphan and 2nd object is
+        // created
+        // try {
+        // obj.finalize(); // Uncaught checked exception
+        // } catch (Throwable e) {
+        // e.printStackTrace();
+        // }
+        System.out.println(obj); // Print 2nd object details
+        System.gc(); // Ignores all unhandled exceptions in finalize()
+        System.out.println("Main completed");
+        // obj = null; // 2nd object becomes orphan
+    }
+
+    void disp() {
+        System.out.println("My message");
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        // throw new java.io.IOException();
+        // System.out.println(10 / 0); // ArithmeticException (unchecked)
+        try {
+            throw new java.io.IOException(); // IOException (checked)
+            // System.out.println(10 / 0); // ArithmeticException (unchecked)
+        } catch (Exception e) {
+            System.out.println(e);
+            // e.printStackTrace(); // Creates an uncaught exception (error)
+        } finally {
+            System.out.println("Finally inside finalize");
+        }
+        System.out.println("Finalize method of FinalizeMethod class invoked");
+    }
+}

IslandOfIsolation.java

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+public class IslandOfIsolation {
+    IslandOfIsolation i;
+
+    public static void main(String[] args) {
+        IslandOfIsolation obj1 = new IslandOfIsolation();
+        IslandOfIsolation obj2 = new IslandOfIsolation();
+
+        obj1.i = obj2;
+        obj2.i = obj1;
+
+        obj1 = null;
+        obj2 = null;
+
+        System.gc();
+
+        System.out.println("Main completed");
+    }
+
+    protected void finalize() throws Throwable {
+        System.out.println("Finalize method invoked");
+    }
+}

StringIntern.java

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+public class StringIntern {
+    public static void main(String[] args) throws Throwable {
+        String s1 = new String("Java");
+        String s2 = "Java";
+        String s3 = "Java";
+        String s4 = s2.intern(); // String s4 = "Java";
+
+        System.out.println(s1 == s2);
+        System.out.println(s3 == s2);
+        System.out.println(s3 == s1);
+        System.out.println(s4 == s2);
+        System.out.println(s4.equals(s2));
+
+        s2 = "C++";
+        System.out.println(s2);
+        s4 = "C++".intern(); // s4 = s2;
+        System.out.println(s4);
+        System.out.println(s4 == s2);
+
+        String str = "null";
+        if (str != null) {
+            if (!str.isEmpty()) {
+                System.out.println(str);
+            } else {
+                System.out.println("Invalid email");
+            }
+        } else {
+            System.out.println("Please provide email address");
+        }
+
+        String s = String.format("|%10d|", 1234);
+        System.out.println(s);
+
+        byte[] b = s2.getBytes();
+        for (int i = 0; i < b.length; i++) {
+            System.out.println(b[i]);
+        }
+    }
+}