https://openjdk.java.net/ 
public interface jdk.internal.jline.console.history.PersistentHistory extends jdk.internal.jline.console.history.History
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: jdk.internal.jline.console.history.PersistentHistory
  super_class: java.lang.Object
{
  public abstract void flush();
    descriptor: ()V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Exceptions:
      throws java.io.IOException

  public abstract void purge();
    descriptor: ()V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Exceptions:
      throws java.io.IOException
}
SourceFile: "PersistentHistory.java"