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 class org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 extends org.bouncycastle.jce.provider.JDKMessageDigest implements java.lang.Cloneable
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.bouncycastle.jce.provider.JDKMessageDigest$SHA1
  super_class: org.bouncycastle.jce.provider.JDKMessageDigest
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 this
         0: .line 58
            aload 0 /* this */
            new org.bouncycastle.crypto.digests.SHA1Digest
            dup
            invokespecial org.bouncycastle.crypto.digests.SHA1Digest.<init>:()V
            invokespecial org.bouncycastle.jce.provider.JDKMessageDigest.<init>:(Lorg/bouncycastle/crypto/Digest;)V
         1: .line 59
            return
        end local 0 // org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lorg/bouncycastle/jce/provider/JDKMessageDigest$SHA1;

  public java.lang.Object clone();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=4, locals=2, args_size=1
        start local 0 // org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 this
         0: .line 64
            aload 0 /* this */
            invokespecial org.bouncycastle.jce.provider.JDKMessageDigest.clone:()Ljava/lang/Object;
            checkcast org.bouncycastle.jce.provider.JDKMessageDigest$SHA1
            astore 1 /* d */
        start local 1 // org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 d
         1: .line 65
            aload 1 /* d */
            new org.bouncycastle.crypto.digests.SHA1Digest
            dup
            aload 0 /* this */
            getfield org.bouncycastle.jce.provider.JDKMessageDigest$SHA1.digest:Lorg/bouncycastle/crypto/Digest;
            checkcast org.bouncycastle.crypto.digests.SHA1Digest
            invokespecial org.bouncycastle.crypto.digests.SHA1Digest.<init>:(Lorg/bouncycastle/crypto/digests/SHA1Digest;)V
            putfield org.bouncycastle.jce.provider.JDKMessageDigest$SHA1.digest:Lorg/bouncycastle/crypto/Digest;
         2: .line 67
            aload 1 /* d */
            areturn
        end local 1 // org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 d
        end local 0 // org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lorg/bouncycastle/jce/provider/JDKMessageDigest$SHA1;
            1    3     1     d  Lorg/bouncycastle/jce/provider/JDKMessageDigest$SHA1;
    Exceptions:
      throws java.lang.CloneNotSupportedException
}
SourceFile: "JDKMessageDigest.java"
NestHost: org.bouncycastle.jce.provider.JDKMessageDigest
InnerClasses:
  public SHA1 = org.bouncycastle.jce.provider.JDKMessageDigest$SHA1 of org.bouncycastle.jce.provider.JDKMessageDigest