A signed int has both negative and positive values. An unsigned int is never ised in Java™. Other languages might used unsigned integers; for example C# has a type called uint, which is unsigned. It runs from 0 to 4294967295 inclusive, whereas the int type has the same range of values in C# and Java™: -2187483648 to 2147483647.
The only unsigned number used in Java™ is the char.