This is for a jar on your classpath in Eclipse, where you have
attached a javadoc zip which Eclipse for some reason dislikes.
NOT attached a valid source jar.
The easiest way is to right-click the jar in question (in the referenced jars, not the physical jar) and choose Preferences -> Javadoc. Here give a correct location (zip/URL) to the correct javadoc. Remember to use the "Validate" button to ensure that it is correctly set up.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…