MXMLFlexJSPublisher contains the following code that is run when no output path is specified in the compiler options:
//begin code String mainClassFolder = configuration.getTargetFileDirectory(); if (mainClassFolder.endsWith("src")) outputParentFolder = new File(configuration.getTargetFileDirectory()).getParentFile(); else if (mainClassFolder.endsWith("src/main/flex") || mainClassFolder.endsWith("src\\main\\flex")) outputParentFolder = new File(configuration.getTargetFileDirectory()).getParentFile().getParentFile().getParentFile(); else outputParentFolder = new File(configuration.getTargetFileDirectory()); //end code In plain English: 1. If the main class is in a src directory, bin will be created in the parent directory of src. 2. If the main class is in a src/main/flex directory (in other words, if it's a Maven project), bin will be created in ../../.. 3. Otherwise, bin will be created in the same directory as the main class. I often use "source" rather than "src", so I was getting source/bin as my output directory, which was unexpected. Rather than hardcoding a couple of special paths, maybe we should create bin relative to the current working directory instead. I think that's a common behavior for command line tools. With this change, both of these commands should continue to work exactly the same way: mxmlc src/Main.mxml mxmlc src/main/flex/Main.mxml I assume that Maven sets the CWD to the correct location before it runs the compiler too. This would also allow other build tools with different project structures to work without modifying the compiler. Thoughts? - Josh