无效的流头:从字节字符串转换对象时的EFBFBDEF

I am trying to convert a ArrayList object to a byte string so it can be sent via sockets. When I run this code it converts to a string properly but when I try to convert it back I get the exception "java.io.StreamCorruptedException: invalid stream header: EFBFBDEF". Other answers I looked at on here didn't really help as I am using the matching ObjectOutputStream and ObjectInputStream. Sorry if there is a simple fix as I am new to working with stream objects.I am trying to convert a ArrayList object to a