scalac(1) Compiler for the Scala 2 language


scalac [ <options> ] <source files>


Command line options. See OPTIONS below.
<source files>
One or more source files to be compiled (such as MyClass.scala).


The compiler has a set of standard options that are supported on the current development environment and will be supported in future releases. An additional set of non-standard options are specific to the current virtual machine implementation and are subject to change in the future. Non-standard options begin with -X.

Standard Options

"none" generates no debugging info,
"source" generates only the source file attribute,
"line" generates source and line number information,
"vars" generates source, line number and local variable information,
"notc" generates all of the above and will not perform tail call optimization.

Generate no warnings
Output messages about what the compiler is doing
Indicate whether source should be compiled with deprecation information; defaults to off (accepted values are: on, off, yes and no)
Available since Scala version 2.2.1

Enable detailed unchecked warnings
Non variable type-arguments in type patterns are unchecked since they are eliminated by erasure
Available since Scala version 2.3.0

-classpath <path>
Specify where to find user class files (on Unix-based systems a colon-separated list of paths, on Windows-based systems, a semicolon-separate list of paths). This does not override the built-in ("boot") search path.
The default class path is the current directory. Setting the CLASSPATH variable or using the -classpath command-line option overrides that default, so if you want to include the current directory in the search path, you must include "." in the new settings.

-sourcepath <path>
Specify where to find input source files.
-bootclasspath <path>
Override location of bootstrap class files (where to find the standard built-in classes, such as "scala.List").
-extdirs <dirs>
Override location of installed extensions.
-d <directory>
Specify where to place generated class files.
-encoding <encoding>
Specify character encoding used by source files.
The default value is platform-specific (Linux: "UTF8", Windows: "Cp1252"). Executing the following code in the Scala interpreter will return the default value on your system:
scala> new

-target: <target>
Specify which backend to use (jvm-1.5,msil).
The default value is "jvm-1.5" (was "jvm-1.4" up to Scala version 2.6.1).

Print program with all Scala-specific features removed
Generates faster bytecode by applying optimisations to the program
Explain type errors in more detail.
Print identifiers with unique names (debugging option).
Print product version and exit.
Print a synopsis of standard options.

Advanced Options

-Xassem <file>
Name of the output assembly (only relevant with -target:msil)
-Xassem-path <path>
List of assemblies referenced by the program (only relevant with -target:msil)
Emit warning on selection of nullable reference
Generate no assertions and assumptions
enable experimental extensions
Disable handling of \u unicode escapes
Parse but ignore annotations in more locations
-Xplugin: <file>
Load a plugin from a file
-Xplugin-disable: <plugin>
Disable a plugin
Print a synopsis of loaded plugins
-Xplugin-opt: <plugin:opt>
Pass an option to a plugin
-Xplugin-require: <plugin>
Abort unless a plugin is available
-Xprint: <phases>
Print out program after <phases> (see below).
Print tree positions (as offsets)
Print tree types (debugging option).
Display a prompt after each error (debugging option).
Compiler stays resident, files to compile are read from standard input.
-Xshow-class <class>
Show class info.
-Xshow-object <object>
Show object info.
Print a synopsis of compiler phases.
-Xsource-reader <classname>
Specify a custom method for reading source files.
-Xscript <object>
Compile as a script, wrapping the code into object.main().

Compilation Phases

initializing compiler
parse source files
create symbols
name and type analysis
reference checking
uncurry function types and applications
lambda lifter
represent types as values
add accessors for constructor arguments
make links from inner classes to enclosing one explicit
add explicit constructor for each class
add tail-calls
perform whole program analysis
add one interface per class
expand mixins by code copying
makes boxing explicit
type eraser
generate icode
enable code generation
compilation terminated
matches all phases


Specify the java command to be used for running the Scala code. Arguments may be specified as part of the environment variable; spaces, quotation marks, etc., will be passed directly to the shell for expansion.
Specify JDK/JRE home directory. This directory is used to locate the java command unless JAVACMD variable set.
Specify the options to be passed to the java command defined by JAVACMD.
With Java 1.5 (or newer) one may for example configure the memory usage of the JVM as follows: JAVA_OPTS="-Xmx512M -Xms16M -Xss16M"
With GNU Java one may configure the memory usage of the GIJ as follows: JAVA_OPTS="--mx512m --ms16m"


Compile a Scala program to the current directory
scalac HelloWorld
Compile a Scala program to the destination directory classes
scalac -d classes HelloWorld.scala
Compile a Scala program using a user-defined java command
env JAVACMD=/usr/local/bin/cacao scalac -d classes HelloWorld.scala
Compile all Scala files found in the source directory src to the destination directory classes
scalac -d classes src/*.scala


scalac returns a zero exist status if it succeeds to compile the specified input files. Non zero is returned in case of failure.


Written by Martin Odersky and other members of the Scala team.


Report bugs to


This is open-source software, available to you under a BSD-like license. See accomponying "copyright" or "LICENSE" file for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.