The IDE is not indicating where (which line) exceptions must be caught nor showing the hint to "surround by try..catch" or "add throws clause", it just showing in the file's icon the red  exclamation (!) 

I have the following class:
public abstract class UTIL {
  //lots of statics methods

	/**
	* Utilities related to Images
	*/
	public final static class Image {

		public static boolean reduceImageQuality(int sizeThreshold, File fileIn, File fileOut) throws IOException { //removing the throws (one or all them)
			// In the body there are many line that throws different Exceptions, non of it are highlighted 
			...
			FileInputStream inputStream = new FileInputStream(file);//FileNotFound
			...
			ImageIO.read(inputStream); //IOException 

		}
		
	}
}

Product Version = NetBeans IDE 8.2 (Build 201609300101)
Operating System = Windows 10 version 10.0 running on amd64
Java; VM; Vendor = 1.8.0_144
Runtime = Java HotSpot(TM) 64-Bit Server VM 25.144-b01

Reproducibility: Happens every time