https://www.graalvm.org/ 
public interface com.oracle.truffle.object.ImmutableMap<K, V> extends java.util.Map<K, V>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.object.ImmutableMap
  super_class: java.lang.Object
{
  public abstract com.oracle.truffle.object.ImmutableMap<K, V> copyAndPut(K, V);
    descriptor: (Ljava/lang/Object;Ljava/lang/Object;)Lcom/oracle/truffle/object/ImmutableMap;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (TK;TV;)Lcom/oracle/truffle/object/ImmutableMap<TK;TV;>;
    MethodParameters:
       Name  Flags
      key    
      value  

  public abstract com.oracle.truffle.object.ImmutableMap<K, V> copyAndRemove(K);
    descriptor: (Ljava/lang/Object;)Lcom/oracle/truffle/object/ImmutableMap;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (TK;)Lcom/oracle/truffle/object/ImmutableMap<TK;TV;>;
    MethodParameters:
      Name  Flags
      key   
}
Signature: <K:Ljava/lang/Object;V:Ljava/lang/Object;>Ljava/lang/Object;Ljava/util/Map<TK;TV;>;
SourceFile: "ImmutableMap.java"