Java is driving software systems, mobile applications and the websites across the world.
Most of us don’t even realize it, but every day, Java is making our life easier. It fuels the software that provides the foundation of modern life.
According to some statistics, more than 3 billion devices around the world run Java.
There’s a good reason why Java is so popular with businesses, software developers, and technology companies.
Years ago, developers struggled to migrate applications across platforms. If you wrote a program for Windows, you’d need to rewrite it for an Apple computer or Mac. Want to use it on UNIX? You’d need to rewrite it again. Each of the cell phone architectures required another rewrite. This made it difficult for software to reach a wide audience across platforms.
It was expensive, time-consuming and and many times cost prohibitive to create an application or program that would run on everything.
Java was built to work independently of platforms and systems. It acts like a virtual system, or Java Virtual Machine (JVM), which can be downloaded and used on almost any platform. With this goal in mind, it’s been designed with as few implementation requirements as possible.
Programmers using Java should be able to write an application once in Java and run it almost anywhere. Applications and programs written in Java work independently of the platform or architecture, with the Java application using the Java instead of the existing architecture, whether it is hardware, an operating system (OS) or website.
Otherwise, Java works as a standard, general purpose programming language. It uses a class-based, object-oriented system. The application is converted to Java bytecode instead of an architecture-specific machine code. Users execute the bytecode with a Java Runtime Environment (JRE) installed on the user’s machine.
Today, Java is one of the most prevalent and popular programming languages in the world, with more than 9 million developers around the world. It’s used for scientific applications, financial systems, software tools, desktop applications, web applications, and mobile apps.
For this article, we’ll review one of the key elements in Java – Strings, Stringbuffer and Stringbuilder. Rather than dive into the technical aspects of strings, we’ll look at how they are used and how you can optimize performance using these tools.
What are Strings in Java?
In Java, Strings are a sequence of characters. For example, a name or word output in Java could be done with a String.
The String in Java is an object, and it represents a sequence of char values. This means you could create and set a char value to the exact character, or you could just set a String with the character you want.
For most, it’s easier and faster to create a String.
Strings are an extremely useful class in Java, however, once you create a String object, it is immutable and cannot be changed. When a Java String changes or a modification is applied to it, an entirely new instance is created.
This means, if you aren’t careful with adding and using strings, you can quickly bog down performance with new (and many times unnecessary) instances as you create operations.
This is where the StringBuilder and StringBuffer class come in.
What are StringBuilder and StringBuffer in Java
StringBuilder and StringBuffer work similarly to a standard Java String, however, both are mutable. The values in StringBuilder and StringBuffer can be changed.
For example, using a concatenation function with String will create an entirely new instance or object. The original String is immutable. There now exists two separate and immutable Strings.
Using the same concatenation function with StringBuilder will allow a change to the actual value of the original string. The value in StringBuilder is modified, so there is no reason to create a new instance or object.
StringBuffer works similarly to StringBuilder, except that StringBuffer is thread safe. Multiple threads can use StringBuffer without a problem or issue.
A thread in Java is the path used when executing a program. Java is a multi-threaded application, but not always is it necessary to utilizes Strings or values in different threads.
Let’s take a look at the rules you should use when selecting String, StringBuilder or StringBuffer.
StringBuffer vs. StringBuilder in Java
Opening the value in a string to change comes with a price in performance for the system. Using StringBuilder instead of String can quickly hurt performance of the program and using StringBuffer when thread-safety isn’t necessary will have a noticeable and negative impact on processing and execution.
Selecting the right class while coding is critical for optimizing output and performance.
There are a few simple String and StringBuffer vs. StringBuilder rules to consider as you work:
- Use String: If a String and String value will remain constant, then use String. String objects are immutable.
- Use StringBuilder: If the String requires operations or logic in the construction, but the String can only be accessed by a single thread, then StringBuilder is the best option.
- Use StringBuffer: If the String will require changes and will be accessed by more than one threads, then StringBuffer is the best option. StringBuffer offers thread-safety. This means if the String will need to pull information from one string to another in multi-threaded application, then StringBuffer should be used.
StringBuffer vs. StringBuilder: Selecting the Right Class
As you are working on a String, you have options for performing operations on the value. For example:
- compare(): Compares the values of two objects (or Strings). Typically implemented with a Comparator<T> interface.
- concat(): Operation to combine two Strings. The second String will be added directly after the first String.
- equals(): Compares objects to check equality, comparing only the values.
- replace(): Removes all old occurrences of a character in a string with a new character.
- split(): Splits a String into substrings base on a delimiter.
- length(): Determines the number of characters in the string.
- compareTo(): Compares the values of the String and determines if they are less, equal or greater than.
These are just a few of accessor methods or options for using Strings. Depending on the function and situation, there may be a better option for each.
Consider if the String in each instance will be mutable or immutable. If values aren’t going to change and will remain constant, then use String.
If the String will change, especially when using the accessor method, but will access only one thread, then you won’t need StringBuffer. StringBuilder will suffice.
If the String will change, and it will also access multiple threads, then you will need thread-safety. You’ll need to use StringBuffer.
Making the Most of StringBuilder and StringBuffer
Java is a powerful tool for developers. It can save time and resources for cross platform programs and applications. It’s a powerful tool for many client-server web applications.
Even so, in the past Java had a reputation, before the release of just-in-time (JIT) compilation, for slow performance and requiring more memory than similar programming languages. Interpreting the Java bytecode on the user machine still affects and negatively impacts program performance even with the JIT compiler in place.
Today, Java is extremely popular with banks and the financial sector, as well as scientific applications and big data applications like Hadoop. Many mobile apps like Google’s Android API use Java as a base. For these industries, Java is safe. The language is easy to maintain and portable, reducing the cost and difficulty of porting applications.
Many of these applications and industries are very demanding on processing. It’s critical programmers and developers reduce weight and pressure on processors when running Java programs and applications.
Creating multiple instances of a String that is no longer referenced in the code can risk a memory leak or worse. These objects can cause the program to become unstable and lead to a crash.
Using the right String class will increase reduce the impact of the program on user hardware and keep your application running smoothly.