jvm crashes inside Arrays.equals()

Question

From the core created I could see that

> A fatal error has been detected by the Java Runtime Environment:
>     #
>     #  SIGSEGV (0xb) at pc=0x00007ffbccaa1b83, pid=1781, tid=0x00007ffbb31ec700
>     #
>     # JRE version: Java(TM) SE Runtime Environment (8.0_181-b25) (build 1.8.0_181-b25)
>     # Java VM: Java HotSpot(TM) 64-Bit Server VM (25.181-b25 mixed mode linux-amd64 compressed oops)
>     # Problematic frame:
>     # J 6754 C2 java.util.Arrays.equals([B[B)Z (54 bytes) @ 0x00007ffbccaa1b83 [0x00007ffbccaa1b60+0x23]

The code were the crash happened is

private List<UnitInfo> unitInfoList = new ArrayList<UnitInfo>();
private final ReentrantReadWriteLock readWriteLock = new ReentrantReadWriteLock();
private final Lock readLock = readWriteLock.readLock();


public UnitInfo getUnitInfoFromIPAddress( InetSocketAddress address )//
    {
        byte[] ipAddress = address.getAddress().getAddress();
        readLock.lock();
        try
        {
            UnitInfo unitInfo;
            Iterator<UnitInfo> list = unitInfoList.iterator();
            while( list.hasNext() )
            {
                unitInfo = list.next();
                if( null != unitInfo.getIpAddress() )
                {
                    if( Arrays.equals( ipAddress, unitInfo.getIpAddress().getAddress() ) )
                    {
                        return unitInfo;
                    }
                }
            }

            return null;
        }
        finally
        {
            //Unlock after completing the read operation.
            readLock.unlock();
        }
    }

Inside the crashed process logs I found many exceptions

Stack Trace Below: null
 java.lang.NullPointerException   at
 java.util.Arrays.copyOf(Arrays.java:3237)
 at common.IpAddress.getAddress(IpAddress.java:161)

Those exceptions appeared in many Threads a little time before and stopped when the process was killed.

public byte[] getAddress()
    {
        byte[] address = null;

        if( IPV4_VAL == version )
        {

                address = Arrays.copyOf(this.address, IPV4_ADDRSIZE);

        }
        else
        {
            address = this.address;
        }
        return address;
    }

Obviously those NullPointers were caused because the byte[] this.address was not initialized and it happened that at the time of execution it was still null. The error happened only once so I am wandering what caused the crash to happen inside Arrays.equals()? This method does not fail if a parameter is null. So was it because of another NullPointer inside copyOf() ? In that case wouldn't I see the the copyOf() in the stack trace of the hss_err file? Could it be a concurrency issue with the Iterator and my readlock?