What does the error T does not match T mean in my Java code?

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SUMMARY

The error "T does not match T" in Java typically arises from type erasure and incorrect casting when using generics. In the provided code, the declaration of the array _underlyingStorage as private T[] _underlyingStorage = (T[]) new Object[128]; leads to a ClassCastException at runtime. This occurs because the generic type T cannot be directly instantiated as an array of type Object. To resolve this, ensure that the generic type is properly handled and consider using an ArrayList instead for dynamic sizing and type safety.

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magnifik
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I am getting compilation errors in the following segment of my code:

_underlyingStorage was declared in the following way: private T[] _underlyingStorage = (T[]) new Object[128];

public T next() {
_currentIndex++;
if(_underlyingStorage[_currentIndex] == _underlyingStorage[_numElements-1])
_underlyingStorage[_currentIndex] = _underlyingStorage[0];
return _underlyingStorage[_currentIndex];
}

the error I'm getting makes no sense to me.. it says that T does not match T. what's happening here?
 
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Where are you getting the error at? I entered everything you had into a class, but I'm not getting any error.
 
magnifik said:
the error I'm getting makes no sense to me.. it says that T does not match T. what's happening here?
Errors reported by the compiler and the runtime are usually very precisely worded, containing a very literal description of a problem in your program and where that problem occurs.

If you aren't yet experienced enough to extract this information from an error, you should copy it verbatim when you ask for others to help. (also, there's probably a line number involved. It would help if you point out which line of your code it refers to)
 

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