Add String class for string operations

src/string/WString.java

@@ -0,0 +1,24 @@
+package string;
+
+import java.util.Arrays;
+
+import thisandthat.WObject;
+
+public class WString extends WObject{
+	String str;
+    
+    public static String generateStringWithLength(int len, char fill){
+    	if(len < 0)
+    		return null;
+    	char[] cs = new char[len];
+    	Arrays.fill(cs, fill);
+    	return new String(cs);
+    }
+
+    /**
+     * Demo
+     * @param args
+     */
+    public static void main(String[] args){
+    }
+}