Not the built-in API - but Guava does, amongst its other treasures. (It's a fabulous library.)
String content = Files.toString(new File("file.txt"), Charsets.UTF_8);
There are similar methods for reading any Readable, or loading the entire contents of a binary file as a byte array, or reading a file into a list of strings, etc.
Note that this method is now deprecated. The new equivalent is:
String content = Files.asCharSource(new File("file.txt"), Charsets.UTF_8).read();
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