Source code taken originally from https://github.com/nomic-ai/gpt4all/tree/main/gpt4all-bindings/java. Configuration assumes that model is located in the same folder as the project folder.

Application.java

package gpt4all;

import com.hexadevlabs.gpt4all.LLModel;

import java.io.File;
import java.nio.file.Path;

public class Application {

    public static void main(String[] args){
        String prompt = "### Human:\nWhat is the meaning of life\n### Assistant:";

        // Replace the hardcoded path with the actual path where your model file resides
        String modelFilePath = System.getProperty("user.dir") + File.separator + "ggml-gpt4all-j-v1.3-groovy.bin";
        
        try (LLModel model = new LLModel(Path.of(modelFilePath))) {
            // May generate up to 4096 tokens but generally stops early
            LLModel.GenerationConfig config = LLModel.config()
                    .withNPredict(4096).build();
            // Will also stream to standard output
            String fullGeneration = model.generate(prompt, config, true);
            
            System.out.println("###");
            System.out.println("[Output] " + fullGeneration);
        } catch (Exception e) {
            // Exceptions generally may happen if the model file fails to load 
            // for a number of reasons such as a file not found. 
            // It is possible that Java may not be able to dynamically load the native shared library or 
            // the llmodel shared library may not be able to dynamically load the backend 
            // implementation for the model file you provided.
            // 
            // Once the LLModel class is successfully loaded into memory the text generation calls 
            // generally should not throw exceptions.
            e.printStackTrace(); // Printing here but in a production system you may want to take some action.
        }
    }

}