double exponentioal notation

public class test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
exByte();
	}
	
	public static void exByte(){
		float f=3.4444f;
		double d=3.4444d;
		d=34444-04;//exponential notation
		System.out.println("d is"+d);
		System.out.println("d==f is"+ d==f);
	}

}

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why above gives compile error.

below why giving false.

public class test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
exByte();
	}
	
	public static void exByte(){
		float f=3.4444f;
		double d=3.4444d;
		d=34444-04;//exponential notation
		System.out.println("d is"+d);
		System.out.println(d==f);
	}

}

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34444e+04 is 3.4444E8

double d=3.4444d;
float f=3.4444f;
d=34444-04;//subtraction notation
System.out.println("d is"+d);
System.out.println("f is"+f);
System.out.println("d==f is"+ (d==f));
d=34444e-04;//exponential notation
System.out.format("d is %.16f\n",d);
System.out.format("f is %.16f\n",f);
System.out.println("d==f is"+ (d==f));

                                 
d is34440.0
f is3.4444
d==f isfalse
d is 3.4444000000000000
f is 3.4444000720977783
d==f isfalse
d is34440.0
d is3.4444E8

public class test4 {

      /**
       * @param args
       */
      public static void main(String[] args) {
            // TODO Auto-generated method stub
exByte();
      }
      
      public static void exByte(){
            float f=3.4444f;
            double d=3.4444d;
            d=34444-04;//exponential notation
            System.out.println("d is"+d);
               System.out.println("d==f is"+ d==f);
            System.out.println("d==f is"+ f==d);
      }

}

both of above bolded lines giving error incomatible types even high precision double assigned to low precision float or vice versa.

please advise

+ has precedence over ==, so "d==f is"+ d==f means ("d==f is"+ d)==f
Those lines should have been
               System.out.println("d==f is"+ (d==f));
            System.out.println("d==f is"+ (f==d));

d=34444-04;//subtraction notation

what it mean by subtraction notation
why it gave output
d is34440.0

Subtracting four from thirty-four thousand four hundred forty-four leaves thirty-four thousand four hundred forty

oh

public class testing {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		double d=3.4444d;
		double d1=3.4444d;
		float f=3.4444f;
		d=34444-04;//subtraction notation
		d1=34444+04;
		System.out.println("d is"+d);
		System.out.println("d1 is"+d1);
		System.out.println("f is"+f);
		System.out.println("d==f is"+ (d==f));
		d=34444e-04;//exponential notation
		System.out.format("d is %.16f\n",d);
		System.out.format("f is %.16f\n",f);
		System.out.println("d==f is"+ (d==f));

	}

}

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above gives

d is34440.0
d1 is34448.0
f is3.4444
d==f isfalse
d is 3.4444000000000000
f is 3.4444000720977783
d==f isfalse

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how it exponential operator different from addition or subtraction. please advise

what it mean by "double exponentioal notation"

The exponential operator would be Math.exp or Math.pow http://docs.oracle.com/javase/7/docs/api/java/lang/Math.html#exp%28double%29 http://docs.oracle.com/javase/7/docs/api/java/lang/Math.html#pow%28double,%20double%29
Exponential (a.k.a. scientific) notation for float or double literals can be expressed using E or e
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html
http://docstore.mik.ua/orelly/java-ent/jnut/ch02_04.htm#INDEX-196

public class testing {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		double d = 3.4444d;
		double d1 = 3.4444d;
		float f = 3.4444f;
		d = 34444 - 04;//subtraction notation
		d1 = 34444 + 04;
		System.out.println("d is" + d);
		System.out.println("d1 is" + d1);
		System.out.println("f is" + f);
		System.out.println("d==f is" + (d == f));
		double d3 = 34444e-04;//exponential notation
		//float f3 = 34444e-04;//exponential notation
		System.out.format("d3 is %.16f\n", d3);
		//System.out.format("f is %.16f\n", f3);
		System.out.println("d==f is" + (d == f));

	}

}

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i got output as

d is34440.0
d1 is34448.0
f is3.4444
d==f isfalse
d3 is 3.4444000000000000
d==f isfalse

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double d3 = 34444e-04;//exponential notation

means like below right
d3=34444*(10 to the power of -4)

which is moving the decimal to left side 4 digits as below
d3 is 3.4444000000000000


i wonder why below line giving compilation error

//float f3 = 34444e-04;//exponential notation

please advise