Programs on ArrayList with proper comments for better understanding

Author: VikramGujar

src/com/lab/dec_30/Test15.java

@@ -0,0 +1,26 @@
+package com.lab.dec_30;
+
+import java.util.ArrayList;
+public class Test15 
+{
+	public static void main(String[] args)
+	{
+		// ArrayList of Stringer type
+		ArrayList<String> list = new ArrayList<>();
+		
+		/*
+		 * String type ArrayList can't hold Integer data
+		list.add(12);
+		list.add(16);
+		list.add(34);
+		list.add(78);
+		*/
+		
+		list.remove(Integer.valueOf(16));
+		
+		System.out.println(list);
+ }
+}
+
+
+

src/com/lab/dec_31/Test11.java

@@ -7,14 +7,19 @@ public class Test11
 {
      public static void main(String[] argv) 
      {
-           Collection c = new ArrayList();
+           Collection c = new ArrayList(); // Arraylist object creation
            c.add("1");
            c.add("2");
            c.add("3");
 
-           Collection c1 = new ArrayList();
+           Collection c1 = new ArrayList(); // Another Arraylist object creation
            c1.add("1");
-           c.retainAll(c1);
+           
+           // retainAll method will compare both c and c1 elements
+           // and c will hold the elements that are smiler
+           c.retainAll(c1);	
+           
+           // will print [1]
            System.out.println(c);
      }
 }

src/com/lab/dec_31/Test12.java

@@ -0,0 +1,22 @@
+package com.lab.dec_31;
+
+import java.util.ArrayList;
+
+public class Test12 
+{
+	public static void main(String[] args)
+	{
+		// String type ArrayList
+		ArrayList<String> list = new ArrayList<String>();
+		
+		list.add(null);		// null
+		list.add(0, "A");	// A null
+		list.add(null);		// A null null
+		list.add(2, "B");	// A null B null
+		list.add("20");		// A null B null 20
+		list.add(1, "C");	// A C null B null 20
+		
+//		will print [ A, C, null, B, null, 20 ]
+		System.out.println(list);
+	}
+}

src/com/lab/dec_31/Test13.java

@@ -0,0 +1,23 @@
+package com.lab.dec_31;
+
+import java.util.ArrayList;
+public class Test13 
+{
+	public static void main(String[] args)
+	{
+		// ArrayList of String type
+		ArrayList<String> list = new ArrayList<>();
+		
+		// Can't hold Integer objects 
+		/*
+		list.add(12);
+		list.add(16);
+		list.add(34);
+		list.add(78);
+		list.remove(12);
+		*/
+		
+		System.out.println(list);
+	}
+}
+	

src/com/lab/dec_31/Test14.java

@@ -0,0 +1,25 @@
+package com.lab.dec_31;
+
+import java.util.ArrayList;
+
+public class Test14 
+{
+	public static void main(String[] args)
+	{
+ 
+		// ArrayList of type String
+		ArrayList<String> list = new ArrayList<>();
+		
+		/*
+		 * String type ArrayList can't hold char type data 
+		list.add('a');
+		list.add('b');
+		list.add('c');
+		list.add('d');
+		list.remove('c');
+		*/
+		System.out.println(list);
+	}
+}
+
+