Safely Casting Long to Int in Java: A Comprehensive Solution

When working with numeric types in Java, it is crucial to ensure that casting operations do not result in data loss. This is especially important when casting long values to int, as the precision of long can exceed that of int.

Java 8: Simplifying the Process

Prior to Java 8, safely casting long to int required a tedious check to verify that the cast did not alter the value. However, with the introduction of Java 8, a new method was added that streamlines this process:

import static java.lang.Math.toIntExact;

long foo = 10L;
int bar = toIntExact(foo);

The toIntExact method throws an ArithmeticException if the cast would result in an overflow, ensuring that data integrity is maintained.

Additional Overflow-Safe Methods

Java 8 also introduced several other overflow-safe methods. These methods all end with "exact" and provide the following functionality:

• Math.incrementExact(long): Increments a long value by one.
• Math.subtractExact(long, long): Subtracts one long value from another.
• Math.decrementExact(long): Decrements a long value by one.
• Math.negateExact(long): Negates a long value.
• Math.subtractExact(int, int): Subtracts one int value from another.

Conclusion

By utilizing the toIntExact method and other overflow-safe methods added in Java 8, developers can confidently cast long values to int without sacrificing data accuracy. This is crucial for maintaining the integrity of numerical computations and ensuring the reliability of code.