Working with Berkeley DB

import com.sleepycat.je.*;
import java.io.*;


// open environment
EnvironmentConfig envCfg = new EnvironmentConfig();
envCfg.setAllowCreate(true);
File f = new File(String.format("%s/data", System.getProperty("user.dir")));
f.mkdir();
Environment env = new Environment(f, envCfg);

// open database
DatabaseConfig dbCfg = new DatabaseConfig();
dbCfg.setAllowCreate(true);
Database db = env.openDatabase(null, dbName, dbCfg);

// key, value placeholders
DatabaseEntry key = new DatabaseEntry();
DatabaseEntry value = new DatabaseEntry();

switch (action) {
    case "list": {
        Cursor cursor = db.openCursor(null, null);
        while (cursor.getNext(key, value, LockMode.DEFAULT) == OperationStatus.SUCCESS)
            System.out.println(new String(key.getData(), "UTF-8") + " -> " + new String(value.getData(), "UTF-8"));
        cursor.close();
        break;
    }
    case "insert": {
        key.setData(keyStr.getBytes("UTF-8"));
        value.setData(valueStr).getBytes("UTF-8"));
        db.put(null, key, value);
        break;
    }
    case "remove": {
        key.setData(keyStr.getBytes("UTF-8"));
        db.delete(null, key);
        break;
    }
    case "get": {
        key.setData(keyStr.getBytes("UTF-8"));
        db.get(null, key, value, LockMode.DEFAULT);
        System.out.println(value.getData() != null ? new String(value.getData(), "UTF-8") : "NULL");
        break;
    }
    default:
}

db.close();
env.close();