Oracle Certification Associate 1Z0-808 - Revision history

Fukakai: /* Primitives */

2020-07-12T18:58:13Z

Primitives

2020-06-22T19:58:52Z

Wrappers

@@ Line 1,161: / Line 1,161: @@
 int getNullInt = numbers.get(0); // null pointer exception
 Integer getNullInteger = numbers.get(0); // null pointer exception
 </source>

2020-06-22T18:39:29Z

Wrappers

← Older revision		Revision as of 20:39, 22 June 2020
Line 1,152:		Line 1,152:
	// List<double> doubleList = new ArrayList<>(); // does not compile - type argument cannot be a primitive type		// List<double> doubleList = new ArrayList<>(); // does not compile - type argument cannot be a primitive type
	List<Double> doubleList = new ArrayList<>();		List<Double> doubleList = new ArrayList<>();
			doubleList.add(10.5); // autoboxing
			double number = doubleList.get(0) // unboxing to primitive

			List<Integer> numbers = new ArrayList<>();
			numbers.add(null);
			numbers.add(null);
			System.out.println(numbers.size()); // 2
			int getNullInt = numbers.get(0); // null pointer exception
			Integer getNullInteger = numbers.get(0); // null pointer exception
	</source>		</source>

2020-06-19T20:43:53Z

ArrayList

← Older revision		Revision as of 22:43, 19 June 2020
Line 1,146:		Line 1,146:
	- Elements are in the same order		- Elements are in the same order
	*/		*/
			</source>

			==Wrappers==
			<source lang= "java">
			// List<double> doubleList = new ArrayList<>(); // does not compile - type argument cannot be a primitive type
			List<Double> doubleList = new ArrayList<>();
	</source>		</source>

2020-06-19T20:41:44Z

ArrayList

← Older revision		Revision as of 22:41, 19 June 2020
Line 1,139:		Line 1,139:
	ArrayList<String> list = new ArrayList<String>(); // second type is not necessary		ArrayList<String> list = new ArrayList<String>(); // second type is not necessary
	list.add(0,"Romain"); // 0 is the index, "Romain" the value/element		list.add(0,"Romain"); // 0 is the index, "Romain" the value/element


			/*
			* .equals() method to compare two arraylist returns true ONLYF IF:
			- Elements are equals
			- Elements are in the same order
			*/
	</source>		</source>

2020-06-11T14:46:17Z

ArrayList

← Older revision		Revision as of 16:46, 11 June 2020
Line 1,130:		Line 1,130:
	</source>		</source>
	=ArrayList=		=ArrayList=
			The array list will automatically resize if you try it with more elements that it can currently hold
	<source lang= "java">		<source lang= "java">
			ArrayList<String> list = new ArrayList<String>(); // second type is not necessary
			ArrayList<String> list = new ArrayList<>(20); // initial capacity of 20
			List<String> list = new ArrayList<>(); // using the interface as type
			// ArrayList<String> list = new List<>(); // does not compile

			ArrayList<String> list = new ArrayList<String>(); // second type is not necessary
			list.add(0,"Romain"); // 0 is the index, "Romain" the value/element
	</source>		</source>

2020-06-11T14:25:03Z

Exam Questions

← Older revision		Revision as of 16:25, 11 June 2020
Line 1,128:		Line 1,128:
	The first size / dimension is always required		The first size / dimension is always required
	*/		*/
			</source>
			=ArrayList=
			<source lang= "java">
	</source>		</source>

2020-06-10T23:06:55Z

Declaration

← Older revision		Revision as of 01:06, 11 June 2020
Line 978:		Line 978:
	int arrayOne[], arrayTwo; // valid - creates one array and one int - Bad Practice		int arrayOne[], arrayTwo; // valid - creates one array and one int - Bad Practice
	//int[20] amyArray; // does not compile - size need to be at the initialization		//int[20] amyArray; // does not compile - size need to be at the initialization
			char[]c = new char[2]; // is valid - even if is missing the space between char[] and "c"
	</source>		</source>

2020-06-10T23:03:53Z

=Nested Loop

← Older revision		Revision as of 01:03, 11 June 2020
Line 1,106:		Line 1,106:
	</source>		</source>

	==Nested Loop=		==Nested Loop==
	'''When a loop contains another loop, it is called "nested loop"'''		'''When a loop contains another loop, it is called "nested loop"'''
	<source lang= "java">		<source lang= "java">
Line 1,114:		Line 1,114:
	}		}
	}		}
			</source>

			==Exam Questions==
			<source lang= "java">
			int[][] scores = new int[5][];
			Object[][][] cubbies = new Object[3][0][5];
			// String beans[] = new beans[6]; // does not compile - it is uses variable name as if it was a type
			java.util.Date[] dates[] = new java.util.Date[2][];
			//int[][] types = new int[]; // does not compile - don't specify any size
			//int[][] java = new int[][]; // does not compile - don't specify any size
			/*
			The first size / dimension is always required
			*/
	</source>		</source>

2020-06-10T22:53:03Z

Multidimensionnal Arrays

@@ Line 1,104: / Line 1,104: @@
 };
 System.out.println(Arrays.toString(threeDArray)); //[[[I@63e31ee, [[I@68fb2c38, [[I@567d299b]
 </source>