How to compare two String in Java - String Comparison Example

String comparison is a common programming task and Java provides several way to compare two String in Java. String is a special class in Java, String is immutable and It’s used a lot in every single Java program starting from simple test to enterprise Java application. In this Java String compare tutorial we will see different ways to compare two String in Java and find out how they compare String and when to use equals() or compareTo() for comparison etc.

Here are four examples of comparing String in Java

1) String comparison using equals method

2) String comparison using equalsIgnoreCase method

2) String comparison using compareTo method

4) String comparison using compareToIgnoreCase method

How to Remove First and Last Character of String in Java - Example Tutorial

You can use the substring() method of java.lang.String class to remove the first or last character of String in Java. The substring() method is overloaded and provides a couple of versions that allows you to remove a character from any position in Java. Alternatively, you can convert String to StringBuffer or StringBuilder and then use its remove() method to remove the first or last character. Both StringBuffer and StringBuilder provides a convenient deleteCharAt(int index) method which removes a character from the corresponding index. You can use this method to remove both first and last characters from String in Java.

How to get first and last character of String in Java - Example

You can get the first and last character of a String using the charAt() method in Java. This method accepts an integer index and returns the corresponding character from String. Since Java String is backed by an array, their index is also zero-based, which means the first character resides at index zero, and the last character is at index, length-1, where length is the number of characters in the String. You can get the length of the String by calling the length() method. The charAt() method is not defined on java.lang.String class, but on its super interface java.lang.CharSequence, hence it will also work for StringBuffer and StringBuilder.

How to check if String is not null and empty in Java? Example

In Java, since null and empty are two different concepts, it's a little bit tricky for beginners to check if a String is both not null and not empty. A String reference variable points to null if it has not been initialized and an empty String is a String without any character or a string of zero length. Remember, a String with just whitespace may not be considered as empty String by one program but considered as empty String by others, so, depending upon your situation, you can include the logic to check for that as well. A String with just white space is also referred to as a blank String in java. In this tutorial, I will teach you a couple of right ways to test if a String is not null and not empty in Java.

When to use intern() method of String in Java? Example

The String.intern() method can be used to deal with the String duplication problem in Java. By carefully using the intern() means you can save a lot of heap memory consumed by duplicate String objects. A String object is said to be duplicated if it contains the same content as another string but occupied a different memory location e.g. str1 != str2 but str1.equals(str2) is true. Since the String object consumes a large amount of heap memory in the average Java application, it makes sense to use the intern() method to reduce duplication and take advantage of the String pool feature provided by Java. You can use the intern() method to intern a String object and store them into the String pool for further reuse.

How to split a comma separated String in Java? Regular Expression Example

You can use the String.split() function or StringTokenizer class to split a comma-separated String in Java. Since splitting a String is a very common functionality, Java designers have provided a couple of split() methods on java.lang.String class itself. These split() function takes a regular expression and split the String accordingly. In order to parse a comma-delimited String, you can just provide a "," as a delimiter and it will return an array of String containing individual values. The split() function internally uses Java's regular expression API (java.util.regex) to do its job.

Why String is Immutable or Final in Java? Explained

The string is Immutable in Java because String objects are cached in the String pool. Since cached String literals are shared between multiple clients there is always a risk, where one client's action would affect all other clients. For example, if one client changes the value of the String "Test" to "TEST", all other clients will also see that value as explained in the first example. Since caching of String objects was important for performance reasons this risk was avoided by making the String class Immutable. At the same time, String was made final so that no one can compromise invariant of String class like Immutability, Caching, hashcode calculation, etc by extending and overriding behaviors. Another reason why the String class is immutable could die due to HashMap.

How to Convert an Array to Comma Separated String in Java - Example Tutorial

The simplest way to convert an array to comma separated String is to create a StringBuilder, iterate through the array, and add each element of the array into StringBuilder after appending the comma. You just need Java 1.5 for that, even if you are not running on Java 5, you can use StringBuffer in place of StringBuilder. The joining of String has got even easier in JDK 8, where you have got the join() method right in the String class itself. The join() method takes a delimiter and a source, which can be an array or collection, and returns a String where each element is joined by a delimiter.

Top 10 Low Latency Tips for Experienced Java Developers

Hello guys, If you are preparing for interviews at High-Frequency Trading (HFT) firms, hedge funds, investment banks, or crypto exchanges, then one thing is guaranteed: You will be asked about low latency systems. Building such systems is a completely different ball game. It’s not just about writing clean code — it's about writing fast code that responds in microseconds. I’ve worked on low-latency Java applications that run in production under tight time constraints, and in this post, I’ll share what I’ve learned in easy Indian English, with some practical examples.

Difference between Stack and Heap memory in Java? Example

The difference between stack and heap memory is a common programming question asked by beginners learning Java or any other programming language. Stack and heap memory are two terms programmers start hearing once they started programming but without any clear and definite explanation. Lack of knowledge of what is a heap in Java and what is stack memory in Java results in misconceptions related to stack and heap. To add to this confusion, a stack is also a data structure that is used to store elements in LIFO(Last In First Out) order and is available in Java API as java.util.Stack.

What is load-on-startup servlet element in web.xml with Example?

load-on-startup is an element that appears inside <servlet> tag in web.xml.4 years back load-on-startup was a very popular servlet interview question because not many Java J2EE developer was familiar with this element and how load-on-startup works inside a servlet container like tomcat or WebSphere. In this J2EE Tutorial, we will see what is a load on startup, how to use the load-on-startup element, and what are different values we can configure for load-On-Startup inside web.xml.

Difference between SendRedirect() and Forward() in JSP Servlet? Example

The difference between SendRedirect and forward is one of the classical interview questions asked during a java web developer interview. This is not just applicable for servlet but also for JSP in which we can use forward action or call sendRedirect() method from scriptlet. Before examining the difference between forward and SendRedirect let’s see what send Redirect method and the forward method does.

SendRedirect ():  

This method is declared in HttpServletResponse Interface.

Signature: void sendRedirect(String url)

Difference between throw and throws in Exception handling - Java Example

Difference between throw and throws keyword on Exception handling in Java is a popular core java interview question. Exception handling being an important part of Java programming language, complete knowledge of all keywords related to exception handling e.g. try, catch, finally, throw and throws is important. Main difference between throw and throws is in there usage and functionality. where throws is used in method signature to declare Exception possibly thrown by any method, throw is actually used to throw Exception in Java code, here is an example of both throw and throws keyword which makes it easy to understand difference between them.

Difference between Struts 1 and Struts 2 Web Development Framework

I had worked previously on Struts 1 but never touched Struts 2, especially since Spring MVC was there to take the leading role. Recently one of my friends ask me to help with Struts2, which leads me to look on the Struts2 framework from start. First thing I wanted to find out differences between Struts 1 and Struts 2 framework, because in my experience, if you have worked in the previous version looking differences between two versions of Struts can quickly help to find, what changes and What are the new features, concepts and improvement is offered by Struts 2. Also the difference between Struts 1 and Struts 2 is a good candidate to include in my list of Struts interview questions for quick revision.

10 points on finalize method in Java – Tutorial Example

finalize method in java is a special method much like the main method in java. finalize() is called before the Garbage collector reclaims the Object, its last chance for any object to perform cleanup activity i.e. releasing any system resources held, closing the connection if open etc. The main issue with finalize() method in Java is it's not guaranteed by JLS that it will be called by Garbage collector or exactly when it will be called, for example, an object may wait indefinitely after becoming eligible for garbage collection and before its finalize() method gets called. similarly even after finalize gets called it's not guaranteed it will be immediately collected.