Java set configuration from text file

Configuration.java

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Properties;

public class Configuration {
	private String resource = null;
	private File file = null;
	private URL res = null;

	public Configuration(String resource) {
		/* resource string example: /com/org/pkg/project.properties */
		super();
		this.resource = resource;
		this.res = getClass().getResource(resource);
	}

	public String getProperty(String key) {

		Properties prop = new Properties();
		InputStream input = null;
		String value = null;

		if (res.toString().startsWith("jar:")) {
			input = getClass().getResourceAsStream(resource);
		} else {
			file = new File(res.getFile());
			try {
				input = new FileInputStream(file.getPath());
			} catch (FileNotFoundException e) {
				e.printStackTrace();
			}
		}

		try {
			prop.load(input);
		} catch (IOException e) {
			e.printStackTrace();
		}

		value = prop.getProperty(key);

		if (input != null){
			try{
				input.close();
			} catch (IOException e){
				e.printStackTrace();
			}
		}

		return value;
	}
}