How to Resolve java.lang.NoSuchMethodError When Using Java 9 Modules (JPMS)

How can I fix the java.lang.NoSuchMethodError when working with Java 9 modules?

// Example code that may cause NoSuchMethodError
public class Example {
    public static void main(String[] args) {
        NewClass newClass = new NewClass();
        newClass.nonExistentMethod(); // This line may cause NoSuchMethodError
    }
}

The `java.lang.NoSuchMethodError` indicates that the Java Virtual Machine (JVM) cannot find a method that it expects to be present at runtime. This error typically occurs when there are mismatches between API versions in modular applications, especially with the introduction of the Java Platform Module System (JPMS) in Java 9.

// Declaring a module in module-info.java
module my.module {
    requires dependency.module;
    exports my.package;
}

Causes

• The method being called has been removed or modified in a newer version of a library.
• Different versions of the same library are being used in your module and in your dependencies.
• Your application’s dependencies have not been updated to be compatible with Java 9 modules.

Solutions

• Ensure that your project's dependencies are compatible with the version of Java you are using.
• Check for conflicting library versions in your module path or classpath.
• Make sure the module that contains the method is properly declared in your `module-info.java` file.

Mistake: Not updating the `module-info.java` file when changing dependencies.

Solution: Always double-check your `module-info.java` to ensure it accurately reflects the required modules.

Mistake: Using libraries that are not modularized in Java 9.

Solution: Look for newer versions of libraries that support JPMS, or use the `--add-modules` option to include non-modular dependencies.