What does the number after "@" mean?
@ is just a separator
Debuggers use the toString method of an object to display its value. And here is description of default implementation of toString method from the javadocs:
The toString method for class Object returns a string consisting of
the name of the class of which the object is an instance, the at-sign
character `@', and the unsigned hexadecimal representation of the hash
code of the object. In other words, this method returns a string equal
to the value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
