10 Simple Coding Tricks to Optimize Performance in Java
1) Use StringBuilder Instead of + Operator
While writing Java code, programmers frequently use the + operator. But the operator consumes additional memory off the heap, and hence affects the application’s performance. The developers can reduce the memory consumption drastically by using StringBuilder instead of + operators. They can further simplify creation of complex strings by using the StringBuilder reference across different methods. They can even replace StringBuffer instances with StringBuilder to reduce additional memory consumption.
2) Avoid Regular Expressions
Often Java developers find it convenient to use regular expressions. But the use of regular expressions can have an adverse impact on the application’s performance. So they must avoid using regular expressions in computation-intensive code sections. In case a developer decides to use regular expressions in computation-intensive code sections, he must not forget to cache the pattern reference. The pattern reference cache will prevent the regular expressions from being compiled frequently.
3) Avoid Iterator and For-Each loop:
Both Iterator and For-Each loop have the ability to make Java code simple and readable. But the programmers must avoid using Iterator () while a string is being looped. When the string is able to iterate a new Iterator instance on the heap is created each time. So the combination of For-Each loop and Iterator can increase memory consumption. The programmers can easily reduce memory consumption by using index-based iterations.
4) Avoid Calling Expensive Methods Directly
Some methods can affect Java application’s performance by consuming extra memory. So the programmers must identify and avoid calling such methods directly. For instance, the JDBC driver will require additional time to calculate the value of the value of the ResultSet.wasNull() function. Instead of calling the expensive methods directly, they can call the cache.
5) Use Primitive Types
The wrapper types can affect Java code’s performance by putting additional pressure of the server. So the developers must explore ways to avoid using wrapper types in their code. They can replace wrapper types by using a number of primitive types and creating one-dimensional arrays of them. Likewise, they can use delimiter variables to indicate the exact location of the encoded object inside the array. It is also a good practice to take advantage of a good collection of primitive collections available in the market.
6) Avoid Recursion
While using modern functional programming languages, programmers commonly used recursion. But the use of recursions can have a negative impact on the Java code processing based on the compiler. There are also chances that the tail-recursive of recursion will affect the algorithm negatively. If the compiler fails to identify the tail-recursive, the entire code will go for a toss. So it is always advisable for Java programmers to use iteration instead of recursion.
7) Use entrySet() with Maps
While working with maps, Java developers often use a variety of map access operations. But many programmers iterate through maps using keys and values. The developer can easily boost the performance of Java application by picking the right map access operations. He must use entrySet() with keys and values to iterate through the map more efficiently. Alternately, he can use the Map.Entry instance to access the map without affecting performance of the Java code.
8) Replace HashSet or HashMap with EnumSet or EnumMap
Sometimes Java programmers use maps with predefined values. For instance, they know the possible keys in a map while using a configuration map. In such scenarios, the programmers can boost the application’s performance by using EnumSet or EnumMap instead of HashSet or HashMap. The array of indexed values makes it easier for Java compiler to identify and insert new values at the time of compilation. EnumMap will increase the map access speed significantly, while consuming lesser memory than HashMap.
9) Enhance hashCode() and equals() Methods
If a programmer decides not to use HashMap, it becomes essential for him to optimize the hashCode() and equals() methods. The optimized hashCode() method will help programmers to prevent calls to equals(). The calls to equals() method consume more memory. Thus, the calls to the expensive method must be minimized to optimize the Java application’s performance.
10) Adopt Functional Programming Concepts
Java is not a 100% functional programming language yet. But the programmers must write Java code in functional programming style to improve the Java application’s performance. They must try to write the code that is more readable and reusable. At the same time, they also need to take advantage of sets, collections, lists and similar options provided by the programming language and various frameworks. The usage of sets will make the algorithm more concise and code more readable.
Oracle Corporation frequently updates Java programming language with new features and enhancements. But many studies have revealed that Java version adoption rate is much slower. Many enterprises still use older versions of the programming language. So the Java application developers must choose the performance optimization techniques according to the version of Java they are using.