assert-api.md

Assertion or Validation Java APIs

📌 Overview of some APIs we can use for assertions.

Production code

API	Class	Example	Exception thrown	Message
JDK	-	assert input != null;	java.lang.AssertionError
JDK	java.util.Objects	Object value = Objects.requireNonNull(input);	java.lang.NullPointerException	🚫
JDK	java.util.Objects	Object value = Objects.requireNonNull(input, "message");	java.lang.NullPointerException	message
Spring	org.springframework.util.Assert	Assert.notNull(input);	java.lang.IllegalArgumentException	[Assertion failed] - the object argument must be null
Spring	org.springframework.util.Assert	Assert.notNull(input, "message");	java.lang.IllegalArgumentException	message
Micronaut	io.micronaut.core.util.ArgumentUtils	ArgumentUtils.requireNonNull("argname", input);	java.lang.NullPointerException	Argument xxx cannot be null
Apache commons-lang3	org.apache.commons.lang3.Validate	Object value = Validate.notNull(input);	java.lang.NullPointerException	The validated object is null
Apache commons-lang3	org.apache.commons.lang3.Validate	Object value = Validate.notNull(input, "message");	java.lang.NullPointerException	message
Google Guava	com.google.common.base.Verify	Verify.verifyNotNull(input);	com.google.common.base.VerifyException	expected a non-null reference

Test code

API	Class	Example	Exception thrown
JUnit 4	junit.framework.Assert	Assert.assertNotNull(input);	junit.framework.AssertionFailedError
JUnit 5	org.junit.jupiter.api.Assertions	Assertions.assertNotNull(input);	org.opentest4j.AssertionFailedError
Hamcrest	org.hamcrest.MatcherAssert	MatcherAssert.asserthat(X, Y);	java.lang.AssertionError
AssertJ	org.assertj.core.api.Assertions	Assertions.asserthat(X, Y);	java.lang.AssertionError
TestNG	org.testng.Assert	Assert.assertNotNull(input);	java.lang.AssertionError