A DESCRIPTION OF THE PROBLEM :
The constructor of ProcessImpl has a structure like this:

if (allowAmbiguousCommands) {
 ...
} else {
            boolean isShell = allowAmbiguousCommands ? isShellFile(executablePath)
                    : !isExe(executablePath);
            cmdstr = createCommandLine(
                    // We need the extended verification procedures
                    isShell ? VERIFICATION_CMD_BAT
                            : (allowAmbiguousCommands ? VERIFICATION_WIN32 : VERIFICATION_WIN32_SAFE),
                    quoteString(executablePath),
                    cmd);
}

These ternary expressions in the else block on allowAmbiguousCommands should be removed, since allowAmbiguousCommands is statically false there.