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.util.encoders.UrlBase64Encoder extends org.bouncycastle.util.encoders.Base64Encoder
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.bouncycastle.util.encoders.UrlBase64Encoder
  super_class: org.bouncycastle.util.encoders.Base64Encoder
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // org.bouncycastle.util.encoders.UrlBase64Encoder this
         0: .line 17
            aload 0 /* this */
            invokespecial org.bouncycastle.util.encoders.Base64Encoder.<init>:()V
         1: .line 19
            aload 0 /* this */
            getfield org.bouncycastle.util.encoders.UrlBase64Encoder.encodingTable:[B
            aload 0 /* this */
            getfield org.bouncycastle.util.encoders.UrlBase64Encoder.encodingTable:[B
            arraylength
            iconst_2
            isub
            bipush 45
            bastore
         2: .line 20
            aload 0 /* this */
            getfield org.bouncycastle.util.encoders.UrlBase64Encoder.encodingTable:[B
            aload 0 /* this */
            getfield org.bouncycastle.util.encoders.UrlBase64Encoder.encodingTable:[B
            arraylength
            iconst_1
            isub
            bipush 95
            bastore
         3: .line 21
            aload 0 /* this */
            bipush 46
            putfield org.bouncycastle.util.encoders.UrlBase64Encoder.padding:B
         4: .line 23
            aload 0 /* this */
            invokevirtual org.bouncycastle.util.encoders.UrlBase64Encoder.initialiseDecodingTable:()V
         5: .line 24
            return
        end local 0 // org.bouncycastle.util.encoders.UrlBase64Encoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    6     0  this  Lorg/bouncycastle/util/encoders/UrlBase64Encoder;
}
SourceFile: "UrlBase64Encoder.java"