Bug 23968 Abusive check on task tags
2.1M1 Java UI ensures that task tags are valid Java identifiers. Why is it so ? JDT/Core supports any type of tags. In particular, "TODO:" should work fine, and was one of the mentionned tags on the original feature request.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/CompilerPreferencePage.java
private static final String PREF_LOCAL_VARIABLE_ATTR=  JavaCore.COMPILER_LOCAL_VARIABLE_ATTR;
	private static final String PREF_LINE_NUMBER_ATTR= JavaCore.COMPILER_LINE_NUMBER_ATTR;
	private static final String PREF_SOURCE_FILE_ATTR= JavaCore.COMPILER_SOURCE_FILE_ATTR;
	private static final String PREF_CODEGEN_UNUSED_LOCAL= JavaCore.COMPILER_CODEGEN_UNUSED_LOCAL;
	private static final String PREF_CODEGEN_TARGET_PLATFORM= JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM;
	private static final String PREF_PB_UNREACHABLE_CODE= JavaCore.COMPILER_PB_UNREACHABLE_CODE;
	private static final String PREF_PB_INVALID_IMPORT= JavaCore.COMPILER_PB_INVALID_IMPORT;
	private static final String PREF_PB_OVERRIDING_PACKAGE_DEFAULT_METHOD= JavaCore.COMPILER_PB_OVERRIDING_PACKAGE_DEFAULT_METHOD;
	private static final String PREF_PB_METHOD_WITH_CONSTRUCTOR_NAME= JavaCore.COMPILER_PB_METHOD_WITH_CONSTRUCTOR_NAME;
	private static final String PREF_PB_DEPRECATION= JavaCore.COMPILER_PB_DEPRECATION;
	private static final String PREF_PB_HIDDEN_CATCH_BLOCK= JavaCore.COMPILER_PB_HIDDEN_CATCH_BLOCK;
	private static final String PREF_PB_UNUSED_LOCAL= JavaCore.COMPILER_PB_UNUSED_LOCAL;
	private static final String PREF_PB_UNUSED_PARAMETER= JavaCore.COMPILER_PB_UNUSED_PARAMETER;
	private static final String PREF_PB_SYNTHETIC_ACCESS_EMULATION= JavaCore.COMPILER_PB_SYNTHETIC_ACCESS_EMULATION;
	private static final String PREF_PB_NON_EXTERNALIZED_STRINGS= JavaCore.COMPILER_PB_NON_NLS_STRING_LITERAL;
	private static final String PREF_PB_ASSERT_AS_IDENTIFIER= JavaCore.COMPILER_PB_ASSERT_IDENTIFIER;
	private static final String PREF_PB_MAX_PER_UNIT= JavaCore.COMPILER_PB_MAX_PER_UNIT;
	private static final String PREF_PB_UNUSED_IMPORT= JavaCore.COMPILER_PB_UNUSED_IMPORT;
	private static final String PREF_PB_STATIC_ACCESS_RECEIVER= JavaCore.COMPILER_PB_STATIC_ACCESS_RECEIVER;
	private static final String PREF_SOURCE_COMPATIBILITY= JavaCore.COMPILER_SOURCE;
	private static final String PREF_COMPLIANCE= JavaCore.COMPILER_COMPLIANCE;
	private static final String PREF_RESOURCE_FILTER= JavaCore.CORE_JAVA_BUILD_RESOURCE_COPY_FILTER;
	private static final String PREF_BUILD_INVALID_CLASSPATH= JavaCore.CORE_JAVA_BUILD_INVALID_CLASSPATH;