JUnit Source Code Files are provided in the source package file, junit-4.13.2-sources.jar.

You can browse JUnit Source Code files below:

⏎ junit/framework/AssertionFailedError.java

package junit.framework;

/**
 * Thrown when an assertion failed.
 */
public class AssertionFailedError extends AssertionError {

    private static final long serialVersionUID = 1L;
    
    /**
     * Constructs a new AssertionFailedError without a detail message.
     */
    public AssertionFailedError() {
    }

    /**
     * Constructs a new AssertionFailedError with the specified detail message.
     * A null message is replaced by an empty String.
     * @param message the detail message. The detail message is saved for later 
     * retrieval by the {@code Throwable.getMessage()} method.
     */
    public AssertionFailedError(String message) {
        super(defaultString(message));
    }

    private static String defaultString(String message) {
        return message == null ? "" : message;
    }
}

⏎ junit/framework/AssertionFailedError.java

Or download all of them as a single archive file:

File name: junit-4.13.2-sources.jar
File size: 234540 bytes
Release date: 2021-02-13
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