NullPointerException – Catch and Fix It

NullPointerException – Are you a coder and facing the error that is related to the thread of Exception in thread “main” java.lang.nullpointerexception then don’t worry you are at the right place for a solution.

As you will proceed with the article here below you are going to find the complete guide that is related to the issue and not only that you will also be shown a step-by-step process that helped you with the solution.

NullPointerException

NullPointerException

Hence before making a second thought, read the article till the end to know more about it.

Exception in Thread “main” java.lang.nullpointerexception

Exception in thread “main” java.lang.nullpointerexception error is probably the first exception you would use when using lava. This is challenging to solve since the name pointer, yet Java does not support many inheritance-like points.

In this article, we include a comprehensive guide on what an error is and how you can fix it. In Java, a null value is assigned to an object as a reference. This indicates that the object points to a piece of unknown data.

Any NullPointerException error means that you are indicating something non-existent. For example, it is like searching for 5th when there are only four spots. This comes when you fail to fill an array of your type. Therefore, this occurs when the reference does not point to a location.

Failing to assign values ​​to each index of your array will cause Java to assign arrays with default values. Java will assign a default value to each array – null. This is how a nullPointerException comes about because Java does not allow null.

While this is a real nightmare for beginners, it is an error that is fairly easy to solve. Before discussing the different ways of addressing an error, it is necessary to understand what it is, why the error occurs, and how to avoid it.

What Exactly is The Exception in Thread Main Java.Lang.Nullpointerexception Error?

Exception in thread “main” java.lang.nullpointerexception error is an error or an exception that occurs when you try to perform an operation with an object that has a null value. The “main” part means that the exception is in the main thread.

Since this is a runtime exception, don’t expect to find a NullPointerException in a program. Having a runtime exception means that the program ends at runtime rather than at compile time.

This Error of “NullPointerException” Can be Found at Times When:

There are circumstances when you can find the error that is going to occur and for that, you should know the alternatives. The errors are the result of:

  1. You call an instance method on any null object
  2. You use or change any variable on a null object
  3. Changing or accessing the null slots of an array
  4. Calling the length of an array if the array is null
  5. You throw avoid when an exception is expected to be thrown
  6. When you use a null in a synchronized Java block, trying to synchronize a null object

As we mentioned earlier, null is a unique value that Java uses. This is required when coding using some design patterns such as singleton patterns or null object patterns. Therefore we need a null value.

A null object pattern acts as a surrogate for a missing object in a particular type; while the singleton pattern ensures that a class instance is created once. For example, declaring constructors private, and later constituting a public method that gives a unique example of the whole type.

Thread Main Java.Lang.Nullpointerexception: How to Fix Exception In Java Error

Now when you have read about the issue occurring points, in order to successfully resolve the NullPointerException error in Java, you first need to identify the cause. It is quite easy to know the reason for the error. Examine only the stack trace of the exception. The stack case will show you the exact line where the NPE has occurred.

Now, go to the line with the error and check for possible object operation. For example, check for an accessing field, an exception, or calling methods. These will point you to the null object.

After identifying the null object, we are halfway there. Understand why the object is invalid, and use the fixes below to resolve the exception. Note that the second part of identifying the error may be different. The tap can be from a factory or a thread.

Since the “main” java.lang.nullpointerexception thread has different causes as you have seen, we cannot limit it to one solution. However, here are these various fixes that are given to you below are going to help you avoid these errors:

  • Hash Tables
  • Argument Method
  • Cryptography Extension Update

Let’s see how these help you to avoid the error:

Hash Tables

This method is about your coding practices. In case you are coding using the Hash Table class then here is the recommended thing for you:

In place of the usual use of Hash Table, you can use a better alternative as HashMap since the former is really old by now.

You can use a file that has ‘Properties file format’.

Argument Method

According to Symantec, if you encounter a problem when trying to run Java LiveUpdate ConfigEditor, it may be that the JCE-Java cryptography extension files need to be updated, or the Live Update configuration file is unreadable. Here is the process that helps you fix the issue via following these steps:

  • First of all, update your JCE policy files.
  • Delete Liveupdate.conf files and then generate a new one.
  • As an alternative to this, you can also correct the Java Path.
  • Note: This fix is directly and solely applicable to Windows 2003 and also 2008.

Cryptography Extension Update

Java code geeks recommend checking the logic of a method. Before performing the body of a method, it is necessary to examine the logic of the process for any null values. After making sure that there alternatively, you can send an “IllegalArguementException” and tell the calling method that something is wrong with the earlier arguments.

Let’s take an Example:

Static int getLength(String s) {

If (s == null)

Throw new IllegalArguementException (“The argument cannot be null”);

Return s. length ( );

}

FAQs

What is Java Lang NullPointerException?

Java.lang.NullPointerException is an error in Java that occurs as a Java program tries to use a null when an object is needed. NullPointerException is a public class that extends RuntimeException.

What causes a null pointer exception?

A null pointer exception is thrown when an application tries to use a null in a case where an object is required. These include: calling the frequency method of a null object. Access or modification in the area of ​​a null object.

Can we catch NullPointerException in Java?

Programs should not hold java.lang.NullPointerException. The NullPointerException exception thrown at runtime indicates the existence of an implicit null pointer dereference that must be fixed in the application code (see EXP01-J. Do not use a null in a case where the object is needed for more information).

Is NullPointerException Checked or Unregistered?

This is not an exception (among other things) because it is extremely common. It can be very much everywhere. If it was checked, almost every method in every single Java program anywhere would be required to declare that it throws NullPointerException. delete LiveUpdate delete LiveUpdate.

Why is the Null Pointer Exception in Selenium WebDriver?

NullPointerException is thrown when an application tries to use a null in a case where an object is needed. … calling the frequency method of a null object. Access or modification in the area of ​​a null object. Taking the length of the null as if it were an array.

What is NullPointerException in Java with an Example?

NullPointerException is a runtime exception and is thrown when the application tries to use an object reference that has a null value. For example, using a method on a null reference.

More Error Fixing Guides:

Conclusion

Remember that any NullPointerException comes about when you use a method on a variable that is not initialized. Therefore, you can avoid the error by always setting a default value for each variable.

Other ways to avoid an exception in the thread main java.lang.nullpointerexception includes using the String.valueOf () method, as opposed to the string () method. For example, if an application code requires a string representation, use the static method instead of the strapping method that throws NPE.

Consider using the ternary operator which is a seven value 1: value 2 as a Boolean expression. Alternatively, you can avoid the error by creating methods that return to empty collections, rather than those that return. Finally, use the Apache `string class. Apache is a library that provides utilities for APUs; For example, string manipulation methods.

Now that we have discussed what the error is, how to fix it, ways to fix it and how to avoid it, you are in a better position to enjoy coding using Java.

Similar Posts

Leave a Reply

Your email address will not be published.