javap no longer finds classes on the extension classpath. This used to work in earlier releases and in Mustang up to b54 but not in more recent builds:

>/java/re/j2se/1.5.0/latest/binaries/solaris-i586/bin/javap -J-showversion com.sun.crypto.provider.SunJCE
java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
Java HotSpot(TM) Server VM (build 1.5.0-b64, mixed mode)

Compiled from DashoA6275
public final class com.sun.crypto.provider.SunJCE extends java.security.Provider{
    static final boolean f;
    static final java.security.SecureRandom g;
    public com.sun.crypto.provider.SunJCE();
    static void a(java.lang.Class);
    static final boolean b(java.lang.Class);
    static {};
}

>/java/re/j2se/6/promoted/all/b54/binaries/solaris-i586/bin/javap -J-showversion com.sun.crypto.provider.SunJCE
java version "1.6.0-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b54)
Java HotSpot(TM) Server VM (build 1.6.0-ea-b54, mixed mode)

Compiled from "DashoA14*.."
public final class com.sun.crypto.provider.SunJCE extends java.security.Provider{
    static final boolean g;
    static final java.security.SecureRandom h;
    public com.sun.crypto.provider.SunJCE();
    static void a(java.lang.Class);
    static final boolean b(java.lang.Class);
    static {};
}

>/java/re/j2se/6/promoted/all/b55/binaries/solaris-i586/bin/javap -J-showversion com.sun.crypto.provider.SunJCE
java version "1.6.0-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b55)
Java HotSpot(TM) Server VM (build 1.6.0-ea-b55, mixed mode)

ERROR:Could not find com.sun.crypto.provider.SunJCE
>