(Solved) Error: Could Not Find or Load Main Class in Java

Introduction

If you’re a Java developer or a student just starting to learn Java, you are likely to encounter the Error: Could not find or load main class at some point. This error can be frustrating, but fortunately, it’s usually easy to fix. In this post, we’ll go over the most common causes of this error and how to solve them.

Solution #1: The Main Class is Not Specified Correctly

One of the most common causes of the “Error: Could not find or load main class” is that the main class is not specified correctly. When you run a Java program, you need to specify the main class that contains the main() method. If you specify the wrong class or if you mistype the class name, you’ll see this error.

To fix this problem, make sure that you are specifying the correct main class and that you have typed the class name correctly. The correct main class looks like below:

public class MainClass {

	public static void main(String[] args) {

               // Do something
	}
}

Solution #2: The Main Class is Not in the Classpath

Another common cause of this error is that the main class is not in the classpath. The classpath is a list of directories and JAR files that Java searches when it needs to find a class. If the main class is not in the classpath, Java won’t be able to find it and you’ll see the “Error: Could not find or load main class” message.

To fix this problem, make sure that the main class is in the classpath. You can specify the classpath when you run the Java program using the -classpath or -cp option. For example:

java -classpath /path/to/main/class MainClass

Solution #3: The Main Class is in a Package

If the main class is in a package, you’ll need to specify the full package name when you run the Java program. For example, if the main class is in the com.example package, you’ll need to specify the full package name like this:

java com.example.MainClass

Make sure to use the correct package name and to use the proper package hierarchy. If you get the package name wrong or if you forget to specify the package, you’ll see the “Error: Could not find or load main class” message.

Solution #5

If you’re still having trouble, try compiling and running your program from the command line using the following command.

Let’s say we have a class HelloWorld.java and it compiled successfully. Then we can execute the following command and it should work.

java -cp ./classes;. HelloWorld

Conclusion

The “Error: Could not find or load main class” is a common error in Java, but it’s usually easy to fix. By following the tips in this post, you should be able to solve this error and get your Java program up and running in no time.