Simple, static, global configuration. Depends on Log4j and Guava.

Config.java

package rmt.analytics.tagger.configuration;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import com.google.common.base.Charsets;
import com.google.common.io.Files;
import com.google.common.io.Resources;

/**
 * Simple, static, global configuration.
 */
public class Config {
    private static Logger logger = LogManager.getLogger("Config");
    public static final String CONFIG_DEFAULTS_FILE = "/configDefaults.properties";
    
    private static Properties props;
    
    static {
        props = new Properties();
        try {
            props.load(Config.class.getResourceAsStream(CONFIG_DEFAULTS_FILE));
        } catch (IOException e) {
            logger.error("Could not load default config file '" + CONFIG_DEFAULTS_FILE + "': " + e.getMessage());
        }
    }
    
    public static void loadConfigFile(String path) {
        try {
            props.load(new FileInputStream(path));
        } catch (Exception e) {
            logger.error("Could not load config file '" + path + "': " + e.getMessage());
        }
    }
    
    public static Object get(String field) {
        Object value = props.get(field);
        if (value==null)
            throw new RuntimeException("Missing property in configuration: " + field);
        else
            return value;
    }
    public static Integer getInteger(String field) {
        return Integer.parseInt(get(field).toString());
    }
    public static Float getFloat(String field) {
        return Float.parseFloat(get(field).toString());
    }
    public static Boolean getBoolean(String field) {
        return Boolean.parseBoolean(get(field).toString());
    }
    public static String getString(String field) {
        return get(field).toString();
    }
    public static String getResourceAsString(String field) {
        try {
            return Resources.toString(Resources.getResource(Config.class, getString(field)), Charsets.UTF_8);
        } catch (Exception e) {
            throw new RuntimeException("Could not load resource '" + getString(field) + "' from config file field '" + field + "': " +
                                       e.getMessage());
        }
    }
    
    public static String getFileAsString(String field) {
        try {
            return Files.toString(new File(getString(field)), Charsets.UTF_8);
        } catch (IOException e) {
            throw new RuntimeException("Could not load File '" + getString(field) + "' from config file field '" + field + "': " +
                                       e.getMessage());
        }
    }
    
    public static boolean containsKey(Object field) {
        return props.containsKey(field);
    }
    
    public static void put(Object field, Object value) {
        props.put(field, value);
    }
    
    private Config() { }
}