java.io.File hat dafür ab Java6 eine API:
Methods to set or query file permissions:
* setWritable(boolean writable, boolean ownerOnly) and setWritable(boolean writable) set the owner's or everybody's write permission
* setReadable(boolean readable, boolean ownerOnly) and setReadable(boolean readable) set the owner's or everybody's read permission
* setExecutable(boolean executable, boolean ownerOnly) and setExecutable(boolean executable) set the owner's or everybody's execute permission