From: 7.1.1 General Form and google/google-java-format#1279 (comment)

7.1.1 General form
The basic formatting of Javadoc blocks is as seen in this example:

/**
 * Multiple lines of Javadoc text are written here,
 * wrapped normally...
 */
public int method(String p1) { ... }

... or in this single-line example:
/** An especially short bit of Javadoc. */
The basic form is always acceptable. The single-line form may be substituted when the entirety of the Javadoc block (including comment markers) can fit on a single line.

Part of #17778, subproblem 1

According to Google Java Style, Javadoc content must begin on the second line after /**, and leading asterisks are treated as part of the content. However, in the following example:

/*************************************************
 * @param str testing.....
 */
public InputCorrectJavadocLeadingAsteriskAlignment(String str) {}

the leading asterisks that appear immediately after /** are treated as Javadoc content. JavadocContentLocation ignores such content because the check explicitly states that content beginning with a leading asterisk is skipped. As a result, this case becomes a false negative, even though the Google Style Guide requires validation of content starting rules.

please, work on this issue after merging #18255