jodd-core/src/main/java/jodd/io/FileUtil.java
public static boolean isBinary(final File file) throws IOException {
		byte[] bytes = readBytes(file, 128);

		for (byte b : bytes) {
			if (b < 32 && b != 9 && b != 10 && b != 13) {
				return true;
			}
		}

		return false;
	}
public static boolean isBinary(final File file) throws IOException {
		byte[] bytes = readBytes(file, 128);

		for (byte b : bytes) {
			if (b < 32 && b != 9 && b != 10 && b != 13) {
				return true;
			}
		}

		return false;
	}
Checks the start of the file for ASCII control characters

@param file {@link File}
@return true if the the start of the {@link File} is ASCII control characters.