When searching classes, usually I remember either part of package and class name or some words from class name, e.g. JDBC and Info in package ucp:
oracle/ucp/jdbc/JDBCConnectionRetrievalInfo.java
oracle/ucp/jdbc/oracle/OracleJDBCConnectionRetrievalInfo.java
oracle/ucp/jdbc/oracle/rlb/OracleDatabaseInstanceInfo.java

Provide an class filter option to use regular expression in the field.