Use ColorConvertOp, this will do the color space conversion. You have several options to set a icc color profile. Either you use a predefined profile by using getInstance with the correct color space constant or you can specify a file, which contains a profile. Here is an example:
ICC_Profile ip = ICC_Profile.getInstance( ColorSpace.CS_sRGB );
ICC_ColorSpace ics = new ICC_ColorSpace( ip );
ColorConvertOp cco = new ColorConvertOp( ics, null );
BufferedImage result = cco.filter( sourceImage, null );
The result will contain an image with the sRGB color space.