Add blopost java programs

Author: gauravkukade

collections/arraylist/arraylist-clear-method-in-java/ArrayListClearMethodExample.java

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+package com.gaurav.ExProject.ArrayList;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A java program to remove all the elements 
+ * of ArrayList using the clear() method.
+ * 
+ * @author Gaurav Kukade at coderolls.com
+ *
+ */
+public class ArrayListClearMethodExample {
+
+	public static void main(String[] args) {
+		
+		// create an arraylist cities
+		List<String> cities = new ArrayList<String>();
+		
+		// add string objects in 'cities'
+		cities.add("New York City");
+		cities.add("Los Angeles");
+		cities.add("Mountain View");
+		cities.add("Austin");
+		cities.add("Atlanta");
+		
+		// printing the cities
+		System.out.println("Before invoking the clear() method");
+		System.out.println("Cities: "+ cities); //print the arraylist with elements
+		System.out.println("cities size: "+ cities.size());
+		
+		//invoke the clear() method on arraylist
+		cities.clear();
+		System.out.println("\nAfter invoking the clear() method");
+		System.out.println("Cities: "+ cities); // empty arraylist
+		System.out.println("cities size: "+ cities.size());
+	}
+}

collections/arraylist/arraylist-contains-method/ArrayListContainsMethodExample.java

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+package com.gaurav.ExProject.ArrayList;
+
+import java.util.ArrayList;
+import java.util.List;
+/**
+ * A java program to check if the ArrayList 
+ * contains the specified element.
+ * 
+ * @author Gaurav Kukade a coderolls.com
+ *
+ */
+public class ArrayListContainsMethodExample {
+
+	public static void main(String[] args) {
+		
+		//create an empty arraylist object 'states'
+		List<String> states = new ArrayList<String>();
+		
+		//add state in the arraylist 
+		states.add("California");
+		states.add("Texas");
+		states.add("Florida");
+		states.add("New Jersey");
+		states.add("Washington");
+		
+		//check if states contains florida
+		boolean isPresent1 = states.contains("Florida");
+		System.out.println("Is Florida present in the list: "+ isPresent1);
+		
+		//check if states contains alaska
+		boolean isPresent2 =states.contains("Alaska");
+		System.out.println("\nIs Alaska present in the list: "+ isPresent2);
+	}
+}

collections/arraylist/arraylist-removerange-method/MyArrayList.java

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+package com.gaurav.ExProject.ArrayList;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A java program to remove the range of elements from 
+ * the MyArraylist (a class which extends the ArrayList)
+ * using the removeRange() method.
+ * 
+ * The removeRange() method is protected and is accessed in class,
+ * subclasses and in a package, but not public.
+ * 
+ * @author Gaurav Kukade at coderolls.com
+ *
+ */
+public class MyArrayList extends ArrayList<String> {
+
+	public static void main(String[] args) {
+		
+		MyArrayList myArrayList = new MyArrayList();
+        
+		myArrayList.add("Monday");
+		myArrayList.add("Tuesday");
+		myArrayList.add("Wednesday");
+		myArrayList.add("Thursday");
+		myArrayList.add("Friday");
+		myArrayList.add("Saturday");
+		myArrayList.add("Sunday");
+        
+        System.out.println("Arraylist before removing range of elments:\n"+ myArrayList);
+  
+        myArrayList.removeRange(2, 4);
+        
+        System.out.println("\nArraylist after removing range of elments:\n"+ myArrayList); 
+	}
+}

java-string/java-reverse-string-using-recursion/ReverseStringUsingRecursion.java

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+package ArrayListAddExample;
+/**
+ * A java program to reverse a striong using recursion.
+ * 
+ * @author gaurav
+ *
+ */
+public class ReverseStringUsingRecursion {
+
+	public static void main(String[] args) {
+		
+		String str = "Hello";
+		System.out.println(reverse(str));
+
+	}
+
+	public static String reverse(String str) {
+	    if ((null == str) || (str.length() <= 1)) {
+	        return str;
+	    }
+	    return reverse(str.substring(1)) + str.charAt(0);
+	}
+}