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Set data structure is used to store unique values only, meaning no duplicate values would be stored in a set. When a HashSet is created, it internally implements a HashMap. An element can be inserted into the HashSet using the ‘add’ function. This internally calls the ‘put’ function since a HashMap would have been internally created. Hence, Set takes in unique values with the help of HashMap.HashMap contains unique key and value pairs, wherein the key and value pairs are inserted using the ‘put’ function. Upon calling the ‘put’ function, a previous value associated with the key or null is ... Read More
The function ‘hashCode’ is used to get the hash code of an object in Java. This is an object of super class Object. It returns the object reference’s memory as an integer. It is a native function, which means no direct method in Java can be used to fetch the reference of the object.For better performace of HashMap, use the hashCode() properly. Basically, this function is used to calculate the bucket and index values. It is defined in the following way −public native hashCode()Since we have mentioned ‘bucket’, it is important to understand what it means. It is an element ... Read More
There are many facts associated with null in Java. We will discuss a few of them here with examples −The default value of any reference variable in Java is always null.Example Live Demopublic class Demo{ private static Object my_obj; public static void main(String args[]){ System.out.println("The default value of object my_obj is : " + my_obj); } }OutputThe default value of object my_obj is : nullA class named Demo defines a static object and the main function that shows the default value of this pre-defined object.The not equal to (!=) and comparison (==) operators can be ... Read More
Java was built by sheer accident, a team of developers were busy building a set top box, and began cleaning C++. When they were winding up these changes, they ended up discovering Java and its runtime environment.Many of you might be aware of this, but for those who aren’t, Java wasn’t the original name that was decided for this language. It was ‘Oak’. Sun Marketing system changed the name later when they realized that a company named ‘Oak’ existed.It is a widely used language all over the world, and is considered to be a favourite amongst the developer group, and ... Read More
There are many interesting facts with respect to increment and decrement operators in Java. We will discuss a few of them with examples −The increment and decrement operators can’t be used with the ‘final’ variables. This is due to the fact that variables associated with ‘final’ keyword can’t be changed −Example Live Demopublic class Demo{ public static void main(String[] args){ final int my_val = 34; int my_val_2 = ++my_val; System.out.println("The value is :"); System.out.println(my_val_2); } }Output/Demo.java:6: error: cannot assign a value to final variable my_val int my_val_2 ... Read More
There are many facts with respect to array assignment, and we will discuss a few of them with working examples here −While creating array object type, the element that would be present inside the array can be declared as type objects or as child class’s object.Example Live Demopublic class Demo{ public static void main(String[] args){ Number[] my_val = new Number[3]; my_val[0] = new Integer(91); my_val[1] = new Double(65.963); my_val[2] = new Double(45.7965); System.out.println(my_val[0]); System.out.println(my_val[1]); System.out.println(my_val[2]); } }Output91 65.963 ... Read More
Java compiler doesn’t allow abandoning an uninitialized local variable. When a local variable is initialized inside a conditional block, there are 3 possibilities that could potentially occur −Code compiles successfully if values are provided in the conditional block and the given condition is true.Code gives a compilation error if variables are provided (instead of values) in the conditional block and the condition is true.Code gives compilation error if the condition that needs to be checked is false.If the local variable is initialized to a default value outside of the conditional block in the code, it won’t give any error and ... Read More
Use the justify-content property with value space-between to add space between the lines.ExampleYou can try to run the following code to implement the space-between value −Live Demo .mycontainer { display: flex; background-color: red; justify-content: space-between; } .mycontainer > div { background-color: white; text-align: center; line-height: 60px; font-size: 30px; width: 100px; margin: 5px; } Quiz Q1 Q2 Q3 Q4
Use the align-content property with value flex-end to set the flex lines in the end.ExampleYou can try to run the following code to implement the flex-end valueLive Demo .mycontainer { display: flex; height: 200px; background-color: blue; align-content: flex-end; flex-wrap: wrap; } .mycontainer > div { background-color: orange; text-align: center; line-height: 60px; font-size: 30px; width: 100px; margin: 5px; } Queue Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8
Increase the size of a flex item, using the flex-grow property. Use it with one or more than flex items.ExampleYou can try to run the following code to implement the flex-grow property. Here Q3 flex-item is larger than other items −Live Demo .mycontainer { display: flex; background-color: orange; align-content: space-between; } .mycontainer > div { background-color: white; text-align: center; line-height: 40px; font-size: 25px; width: 100px; margin: 5px; } Quiz Q1 Q2 Q3 Q4 Q5