ClassCastException in Java — What It Means and How to Fix It

What Java's ClassCastException means and how to fix it.

Published November 2, 2026

ClassCastException is thrown when code attempts to cast an object to a type it isn't actually an instance of.

Key points

  • Read the full stack trace from the top — it names the exact class, method, and line where the exception originated

Example

Object o = "text";\nInteger i = (Integer) o;  // ClassCastException
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