How do you add Test Containers to a Java project?

Maven dependency:

<dependency>
    <groupId>org.testcontainers</groupId>
    <artifactId>junit-jupiter</artifactId>
    <version>1.19.0</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.testcontainers</groupId>
    <artifactId>postgresql</artifactId>
    <version>1.19.0</version>
    <scope>test</scope>
</dependency>

Gradle dependency:

testImplementation 'org.testcontainers:junit-jupiter:1.19.0'
testImplementation 'org.testcontainers:postgresql:1.19.0'

Note: You typically need the core junit-jupiter module plus specific modules for databases/services you're testing.