core/src/main/java/com/orientechnologies/orient/core/db/OrientDB.java
public ODatabaseSession open(String database, String user, String password) {
    return open(database, user, password, OrientDBConfig.defaultConfig());
  }
public ODatabaseSession open(String database, String user, String password) {
    return open(database, user, password, OrientDBConfig.defaultConfig());
  }
Open a database

@param database the database to open
@param user     username of a database user or a server user allowed to open the database
@param password related to the specified username

@return the opened database