In the createP2SHMultiSigInputScript() function of BitcoinJ according to this:

public static Script createP2SHMultiSigInputScript(@NullableList signatures,Script multisigProgram)

Create a program that satisfies a pay-to-script hashed OP_CHECKMULTISIG program. If given signature list is null, incomplete scriptSig will be created with OP_0 instead of signatures

https://bitcoinj.github.io/javadoc/0.12/org/bitcoinj/script/ScriptBuilder.html#createP2SHMultiSigInputScript-java.util.List-org.bitcoinj.script.Script-

the Script multisigProgam input refers to the Redeem Script or the ScriptPubKey??

due to the fact that the createP2SHMultiSigInputScript() returns the ScriptSig script.