Java Compiler

• Javac. This may be the compiler included in the IntelliJ IDEA distribution or a compiler from one of the project JDKs.

• Eclipse (also known as Eclipse Compiler for Java or ECJ). IntelliJ IDEA comes bundled with the Eclipse compiler.

• Groovy-Eclipse. This compiler lets you perform joint compilation of Groovy and Java code using the Eclipse compiler.

• Ajc (the AspectJ compiler).

  The AspectJ compiler is not included in IntelliJ IDEA distribution and should be downloaded separately. For more information, see AspectJ and Using the AspectJ Compiler (ajc).

If no particular version is specified, the bytecode version is defined by the compiler.

To specify different versions for particular modules, use the controls in the Per-module bytecode version area.

Click and select the modules of interest in the dialog that opens. Then, for each of the modules, click the corresponding Target bytecode version cell and select the version from the list.

Use to remove the selected module or modules from the list.

When this option is on and the version of the JDK associated with a module is different from that of the build process JDK, the compiler from the module JDK is used. The exception is when the version of the module JDK is earlier than 1.6. In such cases, the compiler from the build process JDK is used in the cross-compilation mode against the classes of the module JDK.

When the option is off, all the modules are compiled with the same compiler, the one from the build process JDK. When necessary, the cross-compilation mode is used.

To start the build process, the latest of the available JDKs is used. This JDK is chosen from all the JDKs used in your modules, the default project JDK, and also the JDK bundled with IntelliJ IDEA.

IMPORTANT! The choice of the compiler does not affect the source code language level, and also the bytecode target level and linking. That is, irrespective of which compiler is used, the bytecode is linked against the JDK associated with the module, and the resulting code levels are exactly the ones that are specified in your project settings.

Specify the command-line parameters and options to be passed to the compiler at its start. Refer to the compiler documentation for the available options.

If you need more room to type, click to open the Additional command line parameters dialog where the text entry area is larger.

When specifying the parameters and options, follow these rules:

• Use spaces to separate individual parameters and options, for example, -client -ea -Xmx1024m.

• If a parameter or an option includes spaces, enclose the spaces or the argument that contains the spaces in double quotes, for example, some" "arg or "some arg".

• If a parameter or an option includes double quotes (e.g. as part of the argument), escape the double quotes by means of the backslashes, for example, -Dmy.prop=\"quoted_value\".

Type the path in the field, or click and select the required file in the dialog that opens.

If all is well, the compiler version is displayed. Otherwise, an error message is shown. (Using the path and the parameters specified, IntelliJ IDEA tries to launch the compiler with the additional -version parameter.)

You can type the parameters right in the field, or click to open the Command line parameters dialog where the text entry area is larger.

When specifying JVM options, follow these rules:

• Use spaces to separate individual options, for example, -client -ea -Xmx1024m.

• If an option includes spaces, enclose the spaces or the argument that contains spaces in double quotes, for example, some" "arg or "some arg".

• If an option includes double quotes (as part of the argument), escape the double quotes using backslashes, for example, -Dmy.prop=\"quoted_value\".

• You can pass environment variable values to custom Java properties. For example, if you define a variable MY_ENV_VAR, you can pass it to the foo property as follows:

  -Dfoo=${MY_ENV_VAR}

NOTE: The specified parameters are ignored when ajc is used for post-compile weaving.

See also, Optimize compilation performance: Use ajc in combination with javac, Controlling the ajc aspectpath and Fine-tune the use of ajc at a module level.

If this option is off, ajc is used in all cases.

If this option is on, javac is used in addition to or instead of ajc. For example, javac will be used to compile the modules that contain no aspects. As a result, the compilation may become much faster.

See also, Optimize compilation performance: Use ajc in combination with javac and Fine-tune the use of ajc at a module level.

If you need more room to type, click to open the Additional command line parameters dialog where the text entry area is larger.

When specifying the parameters and options, follow these rules:

• Use spaces to separate individual parameters and options, for example, -client -ea -Xmx1024m.

• If a parameter or an option includes spaces, enclose the spaces or the argument that contains the spaces in double quotes, for example, some" "arg or "some arg".

• If a parameter or an option includes double quotes (e.g. as part of the argument), escape the double quotes by means of the backslashes, for example, -Dmy.prop=\"quoted_value\".