if (VM.VerifyAssertions) VM.assert(bcIndex < bcLength);
if (VM.VerifyAssertions) VM._assert(bcIndex < bcLength);
  public final int nextInstruction() {    if (VM.VerifyAssertions) VM.assert(bcIndex < bcLength);    opcode = readUnsignedByte();    wide = (opcode == JBC_wide);    return opcode;  }