[BEAM-6680] Fix {@literal @} that shows up in Javadoc code examples

• Type: Bug
• Status: Resolved
• Priority: P3
• Resolution: Duplicate
• Fix Version/s: Not applicable
• Component/s: sdk-java-core
• Labels: Done
• Assignee: Jeff Klukas
• Reporter: Jeff Klukas
• Created: 15/Feb/19 15:27
• Updated: 06/Oct/20 21:57
• Resolved: 15/Feb/19 16:21

Description

Many Beam classes include multi-line code examples. When annotations need to mark classes or methods in those examples, it looks like we have generally have tried to escape the `@` with a "@literal" tag, but those tags aren't working as expected and end up appearing in the rendered documentation. See ParDo for several examples.

Where `@` appears within a line, no escaping appears to be necessary. It gets a bit complicated when `@` appears as the first non-whitespace character in a line, as is usually the case for annotations on classes or methods. I've proposed a style for handling that case in https://github.com/apache/beam/pull/7852