Provided by: ecj_3.16.0-1~18.04_all 
NAME
ecj - the eclipse JDT Batch Compiler
SYNOPSIS
ecj [OPTION]... [SOURCEFILE]... ...
DESCRIPTION
ecj is the batch compiler from Eclipse and is available as ecj.jar. Since 3.3, this jar also contains
the support for jsr199 (Compiler API) and the support for jsr269 (Annotation processing). In order to use
the annotations processing support, a 1.6 VM is required.
OPTIONS SUMMARY
Here is a summary of all the options, grouped by type. Explanations are in the OPTIONS section.
Module Options
--add-exports --add-modules --add-reads --limit-modules -p|--module-path --module-source-path
--processor-module-path --system
ClassPath Options
-bootclasspath -cp|-classpath -extdirs -endorseddirs -sourcepath -d -encoding
Compliance Options
-target -1.3 -1.4 -1.5 -1.6 -1.7 -1.8 1.9 -source --release
Warning Options
-?:warn -help:warn -warn:... -nowarn -err:... -deprecation -properties
Debug Options
-g -preserveAllLocals -parameters
Annotation Processing Options
-Akey[=value] -proc:[only|none] -processor -processorpath -s -XprintProcessorInfo -XprintRounds
-classNames
Ignored Options (for compatibility with javac options)
-J -X -O
Advanced Options
@<file> -maxProblems -log -Xemacs -proceedOnError -verbose -referenceInfo -progress -time -noExit -repeat
-inlineJSR -enableJavaDoc -missingNullDefault
Helping Options
-? -help -v -version -showversion
OPTIONS
Module Options (Supported from 9 onwards)
--add-exports <source-module>/<package>=<target-module>(,<target-module>)*
A command line form of exports statement which exports the package in source-module to the comma
separated list of target modules.
--add-modules <module 1>,<module 2>,...,<module P>
Extend the default set of root modules with a list of comma separated modules.
--add-reads <source-module>=<target-module>
A command line form of a requires clause equivalent to adding requires source-module in target
modules module-info file.
--limit-modules <module 1>,<module 2>,...,<module P>
Limit the observable modules to the list of comma separated modules.
-p|--module-path <dir 1>;<dir 2>;...;<dir P>
This is a list of directories where application modules can be found. Entries are separated by the
platform path separator.
--module-source-path <dir 1>;<dir 2>;...;<dir P>
This is a list of directories where source files for modules can be found. Entries are separated
by the platform path separator.
--processor-module-path <path>
module path where annotation processors can be found.
--system <jdk>
Override location of system modules.
ClassPath Options
-bootclasspath <dir 1>;<dir 2>;...;<dir P>
This is a list of directories or jar files used to bootstrap the class files used by the compiler.
By default the libraries of the running VM are used. Entries are separated by the platform path
separator. Each directory or file can specify access rules for types between '[' and ']'. If no
bootclasspath is specified, the compiler will infer it using the following system properties
sun.boot.class.path, vm.boot.class.path or org.apache.harmony.boot.class.path in this order
respectively
-cp|-classpath <dir 1>;dir2;...<dir P>
This is a list of directories or jar files used to compile the source files. The default value is
the value of the property "java.class.path". Entries are separated by the platform path separator.
Each directory or file can specify access rules for types between '[' and ']' (e.g. [-X] to forbid
access to type X, [~X] to discourage access to type X, [+p/X:-p/*] to forbid access to all types
in package p but allow access to p/X). The compiler follows the Class-Path clauses of jar files'
manifests recursively and appends each referenced jar file to the end of the classpath, provided
it is not on the classpath yet.
-extdirs <dir 1>;<dir 2>;...;<dir P>
This is a list of directories used to specify the location of extension zip/jar files. Entries are
separated by the platform path separator.
-endorseddirs <dir 1>;<dir 2>;...;<dir P>
This is a list of directories used to specify the location of endorsed zip/jar files. Entries are
separated by the platform path separator.
-sourcepath <dir 1>;<dir 2>;...;<dir P>
This is a list of directories used to specify the source files. Entries are separated by the
platform path separator. Each directory can specify access rules for types between '[' and ']'.
-d <dir 1>|none
This is used to specify in which directory the generated .class files should be dumped. If it is
omitted, no package directory structure is created. If you want to generate no .class file at
all, use -d none.
-encoding <encoding name>
Specify default encoding for all source files. Custom encoding can also be specified on a per file
basis by suffixing each input source file/folder name with [<encoding name>]. For example
X.java[UTF-8] would specify the UTF-8 encoding for the compilation unit X.java located in the
current user directory. If multiple default source file encodings are specified, the last one
will be used.
For example: ... -encoding UTF-8 X.java[Cp1252] Y.java[UTF-16] Z.java ....
All source files will be read using UTF-8 encoding (this includes Z.java). X.java will be read
using Cp1252 encoding and Y.java will be read using UTF-16 encoding.
... -encoding UTF-8 -encoding UTF-16 ....
All source files will be read using UTF-16 encoding. The -encoding option for UTF-8 is ignored.
... -encoding Cp1252 /foo/bar/X.java[UTF-16] /foo/bar[UTF-8] ....
All source files will be read using Cp1252 encoding. X.java is the only file inside the /foo/bar
directory to be read using the encoding UTF-16. All other files in that directory will use UTF-8
encoding.
Compliance Options
-target 1.1 to 1.9 (or 9, 9.0, etc.)
This specifies the .class file target setting. The possible value are:
1.1 (major version: 45 minor: 3)
1.2 (major version: 46 minor: 0)
1.3 (major version: 47 minor: 0)
1.4 (major version: 48 minor: 0)
1.5, 5 or 5.0 (major version: 49 minor: 0)
1.6, 6 or 6.0 (major version: 50 minor: 0)
1.7, 7 or 7.0 (major version: 51 minor: 0)
1.8, 8 or 8.0 (major version: 52 minor: 0)
1.9, 9 or 9.0 (major version: 53 minor: 0)
Defaults are:
1.1 in -1.3 mode
1.2 in -1.4 mode
1.5 in -1.5 mode
1.6 in -1.6 mode
1.7 in -1.7 mode
1.8 in -1.8 mode
1.9 in -1.9 mode clcd1.1 can be used to generate the StackMap attribute.
-1.3 Set compliance level to 1.3. Implicit -source 1.3 -target 1.1.
-1.4 Set compliance level to 1.4 (default). Implicit -source 1.3 -target 1.2.
-1.5 Set compliance level to 1.5. Implicit -source 1.5 -target 1.5.
-1.6 Set compliance level to 1.6. Implicit -source 1.6 -target 1.6.
-1.7 Set compliance level to 1.7. Implicit -source 1.7 -target 1.7.
-1.8 Set compliance level to 1.8. Implicit -source 1.8 -target 1.8.
-1.9 Set compliance level to 1.9. Implicit -source 1.9-target 1.9.
-source 1.1 to 1.9 (or 9, 9.0, etc.)
This is used to specify the source level expected by the compiler. The possible value are:
1.3
1.4
1.5, 5 or 5.0
1.6, 6 or 6.0
1.7, 7 or 7.0
1.8, 8 or 8.0
1.9, 9 or 9.0
Defaults are:
1.3 in -1.3 mode
1.3 in -1.4 mode
1.5 in -1.5 mode
1.6 in -1.6 mode
1.7 in -1.7 mode
1.8 in -1.8 mode
1.9 in -1.9 mode
In 1.4, assert is treated as a keyword. In 1.5 and 1.6, enum and assert are treated as keywords.
--release N
Compile for a specific VM version. Used for compiling against older APIs.
Warning Options
-?:warn -help:warn
Display advanced warning options
-warn:...
Specify the set of enabled warnings.
-warn:none disable all warnings
-warn:<warning tokens separated by ,> enable exactly the listed warnings
-warn:+<warning tokens separated by ,> enable additional warnings
-warn:-<warning tokens separated by ,> disable specific warnings
Examples:
warn:unusedLocal,deprecation
enables only the given two warning options and disables all the other options
warn:-unusedLocal,deprecation,+fallthrough
disables unusedLocal and deprecation, enables fallthrough, and leaves the other warning options
untouched
The first column below shows the default state for an option. A mark "+/-" indicates that an
option covers several fine grained warning variants, some of which are enabled by default, others
disabled. This means that specifying the given option with "+" will enable more warnings than the
default, and specifying "-" disables some that are enabled by default.
+/- allDeadCode dead code including trivial if (DEBUG) check
+/- allDeprecation deprecation even inside deprecated code
- allJavadoc invalid or missing Javadoc
- allOver-ann all missing @Override annotations (superclass and superinterfaces)
- all-static-method all method can be declared as static warnings
+ assertIdentifier occurrence of assert used as identifier
- boxing autoboxing conversion
+ charConcat when a char array is used in a string concatenation without being converted
explicitly to a string
+ compareIdentical comparing identical expressions
- conditionAssign possible accidental boolean assignment
+ constructorName method with constructor name
+ deadCode dead code excluding trivial if (DEBUG) check
- dep-ann missing @Deprecated annotation
+/- deprecation usage of deprecated type or member outside deprecated code
+ discouraged use of types matching a discouraged access rule
- emptyBlock undocumented empty block
+ enumIdentifier occurrence of enum used as identifier
+ enumSwitch incomplete enum switch
- enumSwitchPedantic report missing enum switch cases even in the presence of a default case
- fallthrough possible fall-through case
- fieldHiding field hiding another variable
+ finalBound type parameter with final bound
+ finally finally block not completing normally
+ forbidden use of types matching a forbidden access rule
- hashCode missing hashCode() method when overriding equals()
+/- hiding macro for fieldHiding, localHiding, maskedCatchBlock, and typeHiding
- includeAssertNull raise null warnings for variables that got tainted in an assert expression
- indirectStatic indirect reference to static member
- inheritNullAnnot consider null annotations as being inherited from an overridden method to any
overriding methods
+ intfAnnotation annotation type used as super interface
+ intfNonInherited interface non-inherited method compatibility
- intfRedundant find redundant superinterfaces
- invalidJavadoc macro to toggle the 'malformed Javadoc comments' option and all its sub-options
listed below
- invalidJavadocTag report invalid Javadoc tags in Javadoc comments.
- invalidJavadocTagDep report invalid deprecated references in Javadoc tag arguments
- invalidJavadocTagNotVisible report invalid non-visible references in Javadoc tag arguments
- invalidJavadocVisibility(<visibility>) specify visibility modifier ("public", "protected" or
"private") for malformed Javadoc tag warnings. Usage example: invalidJavadocVisibility(public)
- javadoc invalid Javadoc
- localHiding local variable hiding another variable
+ maskedCatchBlock hidden catch block
- missingJavadocTags macro to toggle the 'missing Javadoc tags' option and all its sub-options
listed below
- missingJavadocTagsMethod report missing Javadoc tags for a method's type parameters
- missingJavadocTagsOverriding report missing Javadoc tags in overriding methods
- missingJavadocTagsVisibility(<visibility>) specify visibility modifier ("public", "protected"
or "private") for missing Javadoc tags warnings. Usage example:
missingJavadocTagsVisibility(public)
- missingJavadocComments macro to toggle the 'missing Javadoc comments' option and all its sub-
options listed below
- missingJavadocCommentsOverriding report missing Javadoc comments in overriding methods
- missingJavadocCommentsVisibility(<visibility>) specify visibility modifier ("public",
"protected" or "private") for missing Javadoc comments warnings. Usage example:
missingJavadocCommentsVisibility(public)
- nls non-nls string literals (lacking of tags //$NON-NLS-<n>)
+ noEffectAssign assignment with no effect
+ nonnullNotRepeated nonnull parameter annotation from overridden method is not repeated in an
overriding method. Is effective only with the nullAnnot option enabled.
+/- null potential missing or redundant null check
- nullAnnot enable annotation based null analysis. If desired, the annotation types to be
interpreted by the compiler can be specified by appending (nullable|nonnull|nonnullbydefault),
where each annotation type is specified using its fully qualified name. Usage example:
nullAnnot(p.Nullable|p.NonNull|p.NonNullByDefault)
Enabling this option enables all null-annotation related sub-options. These can be individually
controlled using options listed below
- nullAnnotConflict report conflicts between null annotation specified and nullness inferred. Is
effective only with the nullAnnot option enabled.
- nullAnnotRedundant report redundant specification of null annotation. Is effective only with
the nullAnnot option enabled.
- nullDereference missing null check
- nullUncheckedConversion report unchecked conversion from unannotated type to @NonNull type. Is
effective only with the nullAnnot option enabled.
- over-ann missing @Override annotation (superclass only)
- paramAssign assignment to a parameter
+ pkgDefaultMethod attempt to override package-default method
+ raw usage a of raw type (instead of a parameterized type)
+/- resource (potentially) unsafe usage of resource of type Closeable
- semicolon unnecessary semicolon or empty statement
+ serial missing serialVersionUID
- specialParamHiding constructor or setter parameter hiding another field
+/- static-access macro for indirectStatic and staticReceiver
- static-method an instance method that could be as a static method
+ staticReceiver if a non static receiver is used to get a static field or call a static method
- super overriding a method without making a super invocation
+ suppress enable @SuppressWarnings
- switchDefault switch statement lacking a default case
- syncOverride missing synchronized in synchronized method override
- syntacticAnalysis perform syntax-based null analysis for fields
- syntheticAccess when performing synthetic access for innerclass
- tasks enable support for tasks tags in source code
+ typeHiding type parameter hiding another type
+ unavoidableGenericProblems report even unavoidable type safety problems due to raw APIs
+ unchecked unchecked type operation
- unnecessaryElse unnecessary else clause
- unqualifiedField unqualified reference to field
+/- unused macro for unusedImport, unusedLabel, unusedLocal, unusedPrivate, unusedThrown,
unusedTypeArgs, and unusedTypeParameter
- unusedAllocation allocating an object that is not used
- unusedArgument unused method parameter (deprecated option; use unusedParam instead)
+ unusedImport unused import reference
+ unusedLabel unused label
+ unusedLocal unused local variable
+ unusedParam unused method parameter
+ unusedParamImplementing unused parameter for implementing method
+ unusedParamIncludeDoc unused parameter documented in a Javadoc comment tag
+ unusedParamOverriding unused parameter for overriding method
+ unusedPrivate unused private member declaration
- unusedThrown unused declared thrown exception
- unusedThrownIncludeDocComment unused declared thrown exception documented in a Javadoc comment
tag
- unusedThrownExemptExceptionThrowable report unused declared thrown exception but exempt
Exception and Throwable
- unusedThrownWhenOverriding unused declared thrown exception in overriding method
+ unusedTypeArgs unused type arguments for method and constructor
+ unusedTypeParameter unused type parameter
- uselessTypeCheck unnecessary cast/instanceof operation
+ varargsCast varargs argument need explicit cast
+/- warningToken unhandled or unused warning token in @SuppressWarnings
-nowarn
No warning (equivalent to -warn:none)
-err:...
Specify the set of enabled warnings that are converted to errors.
E.g.
-err:unusedLocal,deprecation
unusedLocal and deprecation warnings will be converted to errors. All other warnings are still
reported as warnings.
-err:<warning tokens separated by ,> convert exactly the listed warnings to errors
-err:+<warning tokens separated by ,> convert additional warnings to errors
-err:-<warning tokens separated by ,> remove specific warnings from being converted to errors
-deprecation
Equivalent to -warn:+deprecation.
-properties <file>
Set warnings/errors option based on the properties file contents. This option can be used with
-nowarn, -err:.. or -warn:.. options, but the last one on the command line sets the options to be
used.
The properties file contents can be generated by setting project specific settings on an existing
java project and using the file in .settings/org.eclipse.jdt.core.prefs file as a properties file,
or a simple text file that is defined entry/value pairs using the constants defined in the
org.eclipse.jdt.core.JavaCore class. Of those constants declared in this class, all options
starting with "org.eclipse.jdt.core.compiler." are interpreted by the batch compiler.
...
org.eclipse.jdt.core.compiler.problem.annotationSuperInterface=warning
org.eclipse.jdt.core.compiler.problem.assertIdentifier=warning
org.eclipse.jdt.core.compiler.problem.autoboxing=ignore
...
To ensure that a property file has the same effect when used in the IDE and for the batch
compiler, use of the -properties option will change the defaults for a few options:
-g default changed to all enabled
-preserveAllLocals default changed to enabled
-enableJavadoc default changed to enabled
error/warning forbidden default changed to error
Debug Options
-g[:none|:lines,vars,source]
Set the debug attributes level
-g All debug info (equivalent to -g:lines,vars,source)
-g:none No debug info
-g:[lines,vars,source] Selective debug info
Not specifying this option is equivalent to setting -g:lines,source.
-preserveAllLocals
Explicitly request the compiler to preserve all local variables (for debug purpose). If omitted,
the compiler will remove unused locals.
-parameters
Explicitly request the compiler to preserve information about the formal parameters of a method
(such as their names) to be accessed from reflection libraries, annotation processing, code
weaving, and in the debugger. This option is supported from target level 1.8 and later.
Annotation processing options (require a 1.6 VM or above and are used only if the compliance is
1.6)
Annotation Processing Options
-Akey[=value]
Annotation processors options that are passed to annotation processors. key is made of identifiers
separated by dots
-proc:[only|none]
If -proc:only is specified, the annotation processors will run but no compilation will be
performed. If -proc:none is specified, annotation processors will not be discovered or run;
compilation will proceed as if no annotation processors were found. By default the compiler must
search the classpath for annotation processors, so specifying -proc:none may speed compilation if
annotation processing is not required.
-processor <class1[,class2,...]>
Qualified class names of annotation processors to run. If specified, the normal processor
discovery process will be skipped.
-processorpath <dir 1>;<dir 2>;...;<dir P>
A list of directories or jar files which will be searched for annotation processors. Entries are
separated by the platform path separator. If not specified, the classpath will be searched
instead.
-s <dir>
The directory where generated source files will be created.
-XprintProcessorInfo
Print information about which annotations and which elements a processor is asked to process
-XprintRounds
Print information about annotation processing rounds
-classNames <class1[,class2,...]>
Qualified names of binary types that need to be processed
Ignored Options (for compatibility with javac options)
-J<option>
Pass option to the virtual machine
-X<option>
Specify non-standard option. -Xemacs is not ignored.
-X Print non-standard options and exit
-O Optimize for execution time
Advanced Options
@<file>
Read command-line arguments from file
-maxProblems <n>
Max number of problems per compilation unit (100 by default)
-log <filename>
Specify a log file in which all output from the compiler will be dumped. This is really useful if
you want to debug the batch compiler or get a file which contains all errors and warnings from a
batch build. If the extension is .xml, the generated log will be an xml file.
-genericsignature
Explicitly request the compiler to preserve information about generic signature of lambda
expressions.
-Xemacs
Use emacs style to present errors and warnings locations into the console and regular text logs.
XML logs are unaffected by this option. With this option active, the message:
2. WARNING in /workspace/X.java
(at line 8)...
is presented as:
/workspace/X.java:8: warning: The method...
-proceedOnError[:Fatal]
Keep compiling in spite of errors, dumping class files with problem methods or problem types. This
is recommended only if you want to be able to run your application even if you have remaining
errors. With ":Fatal", all optional errors are treated as fatal and this leads to code that will
abort if an error is reached at runtime. Without ":Fatal", optional errors don't prevent the
proper code generation and the produced .class files can be run without a problem.
-verbose
Print accessed/processed compilation units in the console or the log file if specified.
-referenceInfo
Compute reference info. This is useful only if connected to the builder. The reference infos are
useless otherwise.
-progress
Show progress (only in -log mode).
-time Display speed information.
-noExit
Do not call System.exit(n) at end of compilation (n=0 if no error).
-repeat <n>
Repeat compilation process <n> times (perf analysis).
-inlineJSR
Inline JSR bytecode (implicit if target >= 1.5).
-enableJavadoc
Consider references inside Javadoc. The Javadoc options are effective only when this option is
enabled.
-missingNullDefault
When annotation based null analysis is enabled (using "nullAnnot", above), this option will raise
a warning whenever there is no default annotation on a package or a type.
-annotationpath
When annotation based null analysis is enabled (using "nullAnnot", above), this option defines
locations where to find external annotations to support annotation-based null analysis. The value
of this options is a list of directories or zip files. Entries are separated by the platform path
separator. The special name CLASSPATH will cause lookup of external annotations from the
classpath and sourcepath.
Helping Options
-? -help
Display the help message.
-v -version
Display the build number of the compiler. This is very useful to report a bug.
-showversion
Display the build number of the compiler and continue. This is very useful to report a bug.
SEE ALSO
<http://help.eclipse.org/topic/org.eclipse.jdt.doc.user/tasks/task-using_batch_compiler.htm>
BUGS
To report bugs, use <https://bugs.eclipse.org/bugs/enter_bug.cgi?product=JDT&component=Core>
AUTHOR
For details on Eclipse committers, see <http://www.eclipse.org/committers/> 13 March 2017 ecj(1)