Null Pointer Exception Class Implementation in Java

-
Here is the implementation of NullPointerException class in Java : -

  1   /*
    2    * Copyright (c) 1994, 2011, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25  
   26   package java.lang;
   27  
   28   /**
   29    * Thrown when an application attempts to use {@code null} in a
   30    * case where an object is required. These include:
   31    * <ul>
   32    * <li>Calling the instance method of a {@code null} object.
   33    * <li>Accessing or modifying the field of a {@code null} object.
   34    * <li>Taking the length of {@code null} as if it were an array.
   35    * <li>Accessing or modifying the slots of {@code null} as if it
   36    *     were an array.
   37    * <li>Throwing {@code null} as if it were a {@code Throwable}
   38    *     value.
   39    * </ul>
   40    * <p>
   41    * Applications should throw instances of this class to indicate
   42    * other illegal uses of the {@code null} object.
   43    *
   44    * {@code NullPointerException} objects may be constructed by the
   45    * virtual machine as if {@linkplain Throwable#Throwable(String,
   46    * Throwable, boolean, boolean) suppression were disabled and/or the
   47    * stack trace was not writable}.
   48    *
   49    * @author  unascribed
   50    * @since   JDK1.0
   51    */
   52   public
   53   class NullPointerException extends RuntimeException {
   54       private static final long serialVersionUID = 5162710183389028792L;
   55  
   56       /**
   57        * Constructs a {@code NullPointerException} with no detail message.
   58        */
   59       public NullPointerException() {
   60           super();
   61       }
   62  
   63       /**
   64        * Constructs a {@code NullPointerException} with the specified
   65        * detail message.
   66        *
   67        * @param   s   the detail message.
   68        */
   69       public NullPointerException(String s) {
   70           super(s);
   71       }
   72   }



  • you could fine Same thing when you click on NullPointerException from any IDE like Eclipse or netbeans 


Thanks 

Comments

Post a Comment

Popular posts from this blog

Converting JSONArray into CSV file in java

-
package com.loginController; import java.io.File; import org.apache.commons.io.FileUtils; import org.json.CDL; import org.json.JSONArray; import org.json.JSONObject; /**  *  * @author anand  *  */ public class ConvertArray {     public static void main(String myHelpers[]){         String jsonArrayString = "{\"fileName\": [{\"name\": \"Anand\",\"last\": \"Dwivedi\",\"place\": \"Bangalore\"}]}";         JSONObject output;         try {             output = new JSONObject(jsonArrayString);             JSONArray docs = output.getJSONArray("fileName");             File file=new File("JSONSEPERATOR.csv");             String csv = CDL.toString(docs);             FileUtils.writeStringToFile(file, csv);         ...
Read more

Java Design pattern

-
 Singleton Design pattern :-  it's Creational Design Pattern as we need to have only one instance of our class for Ex:- Logger,DBConnector. SingleObject class have its constructor as private and have a static instance of itself. Code:-  public class Singleton { private static Singleton object; private Singleton() { } public static synchronized Singleton getInstance() { if (object == null) object = new Singleton(); return object; } } Eager Initialization :-  public class Singleton { private static Singleton object = new Singleton(); private Singleton() { } public static Singleton getInstance() { return object; } } Double checked Locking :-  public class Singleton { private static volatile Singleton obj = null; private Singleton() { } public static Singleton getInstance() { if (obj == null) { synchronized (Singleton.class) { if (obj == null) obj = new Singleton(); } } ...
Read more

Map class field to map

-
 import java.lang.reflect.Field; import java.util.HashMap; import java.util.Map; public class AutogeneratedClassMapper {     public static Map<String, Object> mapFieldsToMap(Object obj) throws IllegalAccessException {         Map<String, Object> fieldMap = new HashMap<>();         Class<?> clazz = obj.getClass();         Field[] fields = clazz.getDeclaredFields();         for (Field field : fields) {             field.setAccessible(true);             Object value = field.get(obj);             fieldMap.put(field.getName(), value);         }         return fieldMap;     }     // Example usage     public static void main(String[] args) throws IllegalAccessException {         AutogeneratedClass au...
Read more