The <dd> part of definition lists are rendered in monospace font, but should be rendered as regular text.

E.g. see http://download.java.net/jdk9/docs/api/java/util/concurrent/ThreadPoolExecutor.html
After "Core and maximum pool sizes"

Looking at the sources, I see in stylesheet.css:
.contentContainer .description dl dd, .contentContainer .details dl dd, .serializedFormContainer dl dd {
    margin:5px 0 10px 0px;
    font-size:14px;
    font-family:'DejaVu Sans Mono',monospace;
}

which looks dubious and may be the cause of this problem.
Seems to have been added by

# User bpatel
8016549: jdk7 javadocs are hard to read
Reviewed-by: jjg