How Can You Safely Cast a Long to an Int in Java?

Casting Long to Int Safely in Java

Casting a long to an int can potentially result in information loss. To prevent this, it's essential to verify that the cast does not alter the value.

Traditional Approach:

One common approach involves casting to an int and then casting back to a long to check for equality. However, this method has a limitation: it fails for values larger than 2^31-1.

Java 8 Solution:

Java 8 introduced a more robust solution: Math.toIntExact(long). This method throws an ArithmeticException if the cast results in overflow.

<code class="java">long foo = 10L;
int bar = Math.toIntExact(foo); // Throws ArithmeticException on overflow</code>

Other Overflow-Safe Methods:

In addition to toIntExact, Java 8 also added several other overflow-safe methods that end with "exact." These methods include:

• Math.incrementExact(long)
• Math.subtractExact(long, long)
• Math.decrementExact(long)
• Math.negateExact(long)
• Math.subtractExact(int, int)

Using these methods ensures the integrity of your data and prevents unexpected integer overflows.

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