You have given a String and a subString or a character and you need to find out whether given String contains the given character or substring, how would you do that? Well, there are three main ways to search String in Java, the contains() method, the indexOf() method and the lastIndexOf() method, all from java.lang.String class. First method, contains() accepts a CharSequence, superclass of String and return true if that CharSequence appear on the String you have called. The indexOf() and lastIndexOf() are similar method and both return the index (zero based) from where the given subString or character appear in the String you have called. Only difference between indexOf() and lastIndexOf() is that if given substring appear multiple time then they will return difference index, otherwise both will return the same index. Similarly if given sub-string is not present in the String, both will return -1 and contains() will return false.
How to make Immutable class in Java? Mutable vs Immutable Objects
How I make immutable objects in Java? I've always thought that all objects are immutable, because if you change the content of an String example, it will always create you an new String object and point to that. However later I found that String is a special class and its specially designed as an Immutable class because its often cached. Obviously you cannot cache anything which is not constant and that make sense why String is Immutable in Java. But this encouraged me to learn more about Mutable and Immutable class in Java and how to create a custom Immutable class in Java.
Difference between StringTokenizer and Split method in Java? Example
There are multiple ways to split a String in Java, but two of the most common ways are by using StringTokenizer and the split method of String class. You can use either one of them, but when to use which one? This short article will give you some details about StringTokenizer and Split method in Java to decide which one to use.
1) The StringTokenizer is legacy, Prefer split() as more chances of its performance getting improved as happens in Java 7.
2) The StringTokenizer doesn't support regular expression, while spilt() does. However, you need to be careful, because every time you call split, it creates a new Pattern object and compiles expression into a pattern. This means if you are using the same pattern with different input, then consider using Pattern.split() method, because compiling a pattern takes more time later to check whether a given string matches a pattern or not.
1) The StringTokenizer is legacy, Prefer split() as more chances of its performance getting improved as happens in Java 7.
2) The StringTokenizer doesn't support regular expression, while spilt() does. However, you need to be careful, because every time you call split, it creates a new Pattern object and compiles expression into a pattern. This means if you are using the same pattern with different input, then consider using Pattern.split() method, because compiling a pattern takes more time later to check whether a given string matches a pattern or not.
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