In this tutorial you will see how to use putIfAbsent() method in Java HashMap. The putIfAbsent() method inserts the specified value if the passed key is not already present in the HashMap or the key is null. Using this method gives you an option to check if key is already…
In Java Stream API there is a count() method that returns the count of elements in the stream. In this tutorial you’ll learn about count() method with the help of some examples. Java Stream count() method Syntax of the count() method is as follows- long count() count method is a…
In this tutorial you’ll see how to convert a Stream to array using toArray() method of the Java Stream API. Java Stream toArray() method There are two overloaded toArray() methods- Object[] toArray()– Returns an array containing the elements of this stream. toArray(IntFunction<A[]> generator)– This method also returns an array containing…
In this tutorial you’ll see how to convert a Stream to Map using collector method and utility methods like toMap() and groupingBy() of Collectors class in Java Stream API. Syntax of toMap() method is as given below- toMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper) This…
In this tutorial we’ll see how to use Java Stream peek() method with the help of few examples. Syntax of peek() method in Java Stream API Stream<T> peek(Consumer<? super T> action) Argument passed to the peek method is of type Consumer functional interface which represents a non-interfering action to perform…
In this post we’ll see a Java program to find the factorial of a number. Factorial of a non-negative integer n is product of all positive integers less than or equal to n. For example– 5! = 5 X 4 X 3 X 2 X 1 = 120 Factorial program…
Java String split() method splits the string around matches of the given regular expression. The split() method returns string array which contains all the words computed by splitting this string around matches of the given regular expression. In Java String class there are two variants of split() method- String[] split(String…
This post gives an insight into the Java String intern() method which is closely associated with the concept of “interning” strings in Java and maintaining a String pool in Java. String interning in Java In Java, string literals are “interned” so as to share unique instances. A pool of strings,…
To check if a String is null or empty in Java you can use one of the following options. Use isEmpty() method available Java 6 onward to check if the String is empty. Use StringUtils.isEmpty() method of the Apache Commons Lang. From Java 11 onward there is also isBlank() method…
If you want to get specific character of the String by index you can use charAt() method of the String class in Java. charAt() method char charAt(int index)– Returns the char value at the specified index. For a String of length n the passed index should be with in the…
