AbstractJSONConfig.java

import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;

public abstract class AbstractJSONConfig {
	private final String path, name;
	private final File       file;
	private       JSONObject json;
	
	/**
	 * Instantiate a new json configuration file.
	 *
	 * @param path the path to the file
	 * @param name the name of the file
	 */
	public AbstractJSONConfig(String path, String name) {
		this.path = path;
		this.name = name;
		this.file = new File(path + "/" + name + ".json");
	}
	
	/**
	 * Load in the json configuration.
	 *
	 * @param override true to force default, false to use existing or load from default if there is none existing
	 * @return the {@link AbstractJSONConfig}
	 */
	public AbstractJSONConfig load(boolean override) {
		try {
			String fullFile = path + "/" + name + ".json";
			// Attempt to create the file if we need to
			if((file.getParentFile() != null && file.getParentFile().mkdirs()) || file.createNewFile() || override) {
				// Create the new file
				file.createNewFile();
				// Write the default json into the file
				BufferedWriter bw = new BufferedWriter(new FileWriter(file));
				bw.write(this.getDefaultJSON().toString(4));
				bw.close();
			}
			
			// Load in the data from the file
			json = this.readJSONFile(new FileInputStream(file));
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return this;
	}
	
	/**
	 * Read in the json file from the input stream.
	 *
	 * @param inputStream the {@link FileInputStream}
	 * @return the {@link JSONObject}
	 */
	private JSONObject readJSONFile(FileInputStream inputStream) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
			StringBuilder sb = new StringBuilder();
			String line;
			while((line = br.readLine()) != null)
				sb.append(line);
			br.close();
			if(sb.toString().equals(""))
				sb.append("{}");
			return new JSONObject(sb.toString());
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return null;
	}
	
	/**
	 * Get the path for the config.
	 *
	 * @return the path
	 */
	public String getPath() {
		return path;
	}
	
	/**
	 * Get the name for the config.
	 *
	 * @return the file name
	 */
	public String getName() {
		return name;
	}
	
	/**
	 * Get the file for the config.
	 *
	 * @return the {@link File}
	 */
	public File getFile() {
		return file;
	}
	
	/**
	 * Get the json for the config.
	 *
	 * @return the {@link JSONObject}
	 */
	public JSONObject getJSON() {
		return json;
	}
	
	/**
	 * Get the section of the configuration file given the parent section.
	 *
	 * @param parent the parent {@link JSONObject} (mainly the first json)
	 * @param key the key
	 * @return the {@link JSONObject}; creates empty {@link JSONObject} if it doesn't exist
	 */
	public JSONObject getSection(JSONObject parent, String key) {
		JSONObject section = parent.getJSONObject(key);
		if(section == null) section = new JSONObject();
		return section;
	}
	
	/**
	 * Get the section of the configuration file from the first json.
	 *
	 * @param key the key
	 * @return the {@link JSONObject}; creates empty {@link JSONObject} if it doesn't exist
	 */
	public JSONObject getSection(String key) {
		return this.getSection(json, key);
	}
	
	/**
	 * Save the json into the file.
	 */
	public void save() {
		// Do not save if the file is null, as it is abstractly defined
		if(file == null) return;
		try {
			// Convert the JSONObject to a 4 spaced-indented string format
			String json = this.json.toString(4);
			// Save the current content of the JSONObject into the File
			BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), StandardCharsets.UTF_8));
			bw.write(json);
			bw.close();
		} catch (IOException ex) {
			ex.printStackTrace();
		}
	}
	
	/**
	 * Generate the default json object for the configuration.
	 *
	 * @return the default {@link JSONObject}
	 */
	protected abstract JSONObject getDefaultJSON();
}

JSONConfig.java

import org.json.JSONObject;

public class JSONConfig extends AbstractJSONConfig {
	public JSONConfig(String path, String name) {
		super(path, name);
	}
	
	@Override
	public JSONConfig load(boolean override) {
		return (JSONConfig) super.load(override);
	}
	
	@Override
	public JSONObject getDefaultJSON() {
		return new JSONObject();
	}
}