http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5. 
public abstract class org.bouncycastle.asn1.ASN1Null extends org.bouncycastle.asn1.ASN1Object
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: org.bouncycastle.asn1.ASN1Null
  super_class: org.bouncycastle.asn1.ASN1Object
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.asn1.ASN1Null this
         0: .line 11
            aload 0 /* this */
            invokespecial org.bouncycastle.asn1.ASN1Object.<init>:()V
         1: .line 13
            return
        end local 0 // org.bouncycastle.asn1.ASN1Null this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lorg/bouncycastle/asn1/ASN1Null;

  public int hashCode();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.asn1.ASN1Null this
         0: .line 17
            iconst_m1
            ireturn
        end local 0 // org.bouncycastle.asn1.ASN1Null this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/asn1/ASN1Null;

  boolean asn1Equals(org.bouncycastle.asn1.DERObject);
    descriptor: (Lorg/bouncycastle/asn1/DERObject;)Z
    flags: (0x0000) 
    Code:
      stack=1, locals=2, args_size=2
        start local 0 // org.bouncycastle.asn1.ASN1Null this
        start local 1 // org.bouncycastle.asn1.DERObject o
         0: .line 23
            aload 1 /* o */
            instanceof org.bouncycastle.asn1.ASN1Null
            ifne 2
         1: .line 25
            iconst_0
            ireturn
         2: .line 28
      StackMap locals:
      StackMap stack:
            iconst_1
            ireturn
        end local 1 // org.bouncycastle.asn1.DERObject o
        end local 0 // org.bouncycastle.asn1.ASN1Null this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lorg/bouncycastle/asn1/ASN1Null;
            0    3     1     o  Lorg/bouncycastle/asn1/DERObject;
    MethodParameters:
      Name  Flags
      o     

  abstract void encode(org.bouncycastle.asn1.DEROutputStream);
    descriptor: (Lorg/bouncycastle/asn1/DEROutputStream;)V
    flags: (0x0400) ACC_ABSTRACT
    Exceptions:
      throws java.io.IOException
    MethodParameters:
      Name  Flags
      out   

  public java.lang.String toString();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.asn1.ASN1Null this
         0: .line 36
            ldc "NULL"
            areturn
        end local 0 // org.bouncycastle.asn1.ASN1Null this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/asn1/ASN1Null;
}
SourceFile: "ASN1Null.java"