$ cat Test.java 
/**
 * standard inline tag: {@code a < b} , parsed ok.
 * standard inline tag: {@code a<b} , parsed ok.
 * Non standard {@preformat a < b} parsed ok.
 */
public class Test {
}

$ java -jar checkstyle-7.6-all.jar -J Test.java
CLASS_DEF -> CLASS_DEF [6:0]
|--MODIFIERS -> MODIFIERS [6:0]
|   |--BLOCK_COMMENT_BEGIN -> /* [1:0]
|   |   |--COMMENT_CONTENT -> *\n * standard inline tag: {@code a < b} , parsed ok.\n * standard inline tag: {@code a<b} , parsed ok.\n * Non standard {@preformat a < b} parsed ok.\n  [1:2]
|   |   |   `--JAVADOC -> \n * standard inline tag: {@code a < b} , parsed ok.\n * standard inline tag: {@code a<b} , parsed ok.\n * Non standard {@preformat a < b} parsed ok.\n <EOF> [1:3]
|   |   |       |--NEWLINE -> \n [1:3]
|   |   |       |--LEADING_ASTERISK ->  * [2:0]
|   |   |       |--TEXT ->  standard inline tag:  [2:2]
|   |   |       |--JAVADOC_INLINE_TAG -> {@code a < b} [2:24]
|   |   |       |   |--JAVADOC_INLINE_TAG_START -> { [2:24]
|   |   |       |   |--CODE_LITERAL -> @code [2:25]
|   |   |       |   |--WS ->   [2:30]
|   |   |       |   |--TEXT -> a < b [2:31]
|   |   |       |   `--JAVADOC_INLINE_TAG_END -> } [2:37]
|   |   |       |--TEXT ->  , parsed ok. [2:38]
|   |   |       |--NEWLINE -> \n [2:51]
|   |   |       |--LEADING_ASTERISK ->  * [3:0]
|   |   |       |--TEXT ->  standard inline tag:  [3:2]
|   |   |       |--JAVADOC_INLINE_TAG -> {@code a<b} [3:24]
|   |   |       |   |--JAVADOC_INLINE_TAG_START -> { [3:24]
|   |   |       |   |--CODE_LITERAL -> @code [3:25]
|   |   |       |   |--WS ->   [3:30]
|   |   |       |   |--TEXT -> a<b [3:31]
|   |   |       |   `--JAVADOC_INLINE_TAG_END -> } [3:35]
|   |   |       |--TEXT ->  , parsed ok. [3:36]
|   |   |       |--NEWLINE -> \n [3:49]
|   |   |       |--LEADING_ASTERISK ->  * [4:0]
|   |   |       |--TEXT ->  Non standard  [4:2]
|   |   |       |--JAVADOC_INLINE_TAG -> {@preformat a < b} [4:16]
|   |   |       |   |--JAVADOC_INLINE_TAG_START -> { [4:16]
|   |   |       |   |--CUSTOM_NAME -> @preformat [4:17]
|   |   |       |   |--WS ->   [4:27]
|   |   |       |   |--DESCRIPTION -> a < b [4:28]
|   |   |       |   |   `--TEXT -> a < b [4:28]
|   |   |       |   `--JAVADOC_INLINE_TAG_END -> } [4:33]
|   |   |       |--TEXT ->  parsed ok. [4:34]
|   |   |       |--NEWLINE -> \n [4:45]
|   |   |       |--TEXT ->   [5:0]
|   |   |       `--EOF -> <EOF> [5:1]
|   |   `--BLOCK_COMMENT_END -> */ [5:1]
|   `--LITERAL_PUBLIC -> public [6:0]
|--LITERAL_CLASS -> class [6:7]
|--IDENT -> Test [6:13]
`--OBJBLOCK -> OBJBLOCK [6:18]
    |--LCURLY -> { [6:18]
    `--RCURLY -> } [7:0]

$ cat Test.java 
/**
 * standard inline tag: {@code a < b} , parsed ok.
 * standard inline tag: {@code a<b} , parsed ok.
 * Non standard {@preformat a < b} parsed ok.
 * Non standard {@preformat a<b} parsed with error.
 */
public class Test {
}

$ java -jar checkstyle-7.6-all.jar -J Test.java
Exception in thread "main" java.lang.IllegalArgumentException: [ERROR:5] Javadoc comment at column 32 has parse error. Details: no viable alternative at input '<b}' while parsing HTML_ELEMENT
	at com.puppycrawl.tools.checkstyle.DetailNodeTreeStringPrinter.parseJavadocAsDetailNode(DetailNodeTreeStringPrinter.java:71)
	at com.puppycrawl.tools.checkstyle.AstTreeStringPrinter.parseAndPrintJavadocTree(AstTreeStringPrinter.java:117)
	at com.puppycrawl.tools.checkstyle.AstTreeStringPrinter.printJavaAndJavadocTree(AstTreeStringPrinter.java:99)
	at com.puppycrawl.tools.checkstyle.AstTreeStringPrinter.printJavaAndJavadocTree(AstTreeStringPrinter.java:103)
	at com.puppycrawl.tools.checkstyle.AstTreeStringPrinter.printJavaAndJavadocTree(AstTreeStringPrinter.java:103)
	at com.puppycrawl.tools.checkstyle.AstTreeStringPrinter.printJavaAndJavadocTree(AstTreeStringPrinter.java:103)
	at com.puppycrawl.tools.checkstyle.AstTreeStringPrinter.printJavaAndJavadocTree(AstTreeStringPrinter.java:82)
	at com.puppycrawl.tools.checkstyle.Main.runCli(Main.java:333)
	at com.puppycrawl.tools.checkstyle.Main.main(Main.java:174)