Java Code Optimization

We encounter the idea of optimization while working on any Java application. It is essential that the code we write is not only clear and error-free but also optimized, meaning that the amount of time it takes to run should be within the predetermined range. To accomplish this, we must consult the Java coding standards and check our code to ensure that it complies. Due to time constraints, however, we occasionally don't have enough to review the code. In these situations, we're offering some advice that a developer can bear in mind when implementing any requirement, reducing the amount of code modifications necessary to fix performance issues during testing or before sending the code into production.

Business optimization and technical optimization are two categories of performance optimization. Large-scale effects of business optimization fall under the management and product categories. Regardless of the language being utilized, there are a few standard optimization strategies. Some of these solutions, such global register allocation, are complex ways to distribute machine resources (like CPU registers), and they don't apply to Java bytecodes. We'll concentrate on methods that essentially restructure code by replacing equivalent operations with other ones.

As developers, we must achieve the set optimization goals in our daily work primarily by using a variety of technical tools. The planning of storage and processing resources is the main emphasis of optimization. In optimization strategies, there are various ways to trade off space for time, however it is not advisable to focus solely on calculation speed without taking complexity and space constraints into account.

Optimization is one of the major concerns when working with Java applications. The execution time of our code must be within the specified range, and it must be free of bugs and optimized.

Given that we occasionally lack the time to study the code, we should take into account the standards set forth by Java in this regard.

Writing well-performing applications is tricky, no matter the language or platform you use, and Java is no exception.

Besides the common problems, Java performance tuning presents its own intrinsic challenges. For a quick example, think of the double-edged sword that is garbage collection. Writing functional code is one thing. What about clear, accessible, and brief code, though? That is absolutely different. to develop an app that addresses a single issue. Not too difficult. How about one that not only provides a solution but is also simple and enjoyable to use? Now we're conversing.

I will summarize some of the tools and techniques often used for performance optimization, and through doing so, I will also try to show how performance optimization works. This article will be divided into four parts. The primary part will provide an overview about the idea behind implementing optimization. The second part will introduce the general process involved with performance optimization and some common misconceptions. Next, the third part will discuss some worthwhile performance troubleshooting tools and common performance bottlenecks you should be aware of. Last, the fourth part will bring together the tools introduced previously to describe some common optimization methods that are focused on improving CPU, memory, network, and service performance.

Note that unless otherwise stated, terminology like thread, heap, garbage collection, and others that are presented here pertain to concepts that are similar in Java applications. The same justification could be used for several software properties, which would result in a lengthy article. Instead, let’s focus on only one of those properties: performance.

That doesn’t mean that optimizing your apps is a lost battle, nor that you must be an expert in order to do so. You may make a high-performing application by adhering to a number of simple guidelines and best practices.

That’s what today’s post is about. We’re going to show you 11 tips to help you optimize your Java applications. So, unsurprisingly, most of these recommendations will be Java-specific.

However, there are a few of language-neutral ones that work with all programmers and programming languages.

We’re going to cover all the tips, starting with the ones that are language agnostic, and progressing to the ones more specific to the Java platform. Let’s get started.

Reuse Optimization

The repetitive code you write can often be removed and turned into public methods so that you don't have to write it again.

Reusing this concept. The coding algorithm described above has been optimized, and the multiplexing scenario for data access is the same. In both life and coding, repeating events frequently occur. Without reuse, life and work would be more exhausting.

The first things that come to mind when we think of data multiplexing in software systems are buffering and caching. Keep in mind that these two words have very different meanings from one another. Here is a quick overview.

Data is frequently briefly stored in a buffer before being sent or written in batches. The sequential approach is used to reduce the number of slow and frequent random writes between various devices. Mostly write operations take place in the buffer.

By caching the reading data in a reasonably high-speed location, cache is frequently employed for multiplexing reading data. The cache mostly facilitates reading actions.

Like this, Java regularly uses object pooling activities like database connection pools, thread pools, etc.

12 Tips to Optimize Java Code Performance

We will temporarily store these objects after using them so that we won't have to repeat the time-consuming initialization step the next time we use them. This is because the cost of generating and deleting these objects is relatively significant.

• Avoid Writing Long Methods:
  The techniques used should be concise and focused on a single feature. Since the method is loaded in stack memory during class loading and method call, it is better for maintenance and performance. When techniques are too complex and take up too much processing time, memory and CPU time are used up during execution. Aim to divide the methods into smaller ones at appropriate logical intersections.
  
• Avoid Multiple If-else Statements:
  Our code makes decisions using conditional statements. Avoid using conditional statements excessively. Performance will be impacted if we use too many conditional if-else statements since JVM will need to compare the conditions. If the same is used in looping statements like for, while, etc., this could get worse. If your business logic contains too many criteria, try grouping them to provide a Boolean result that can be used in the if statement. Additionally, if possible, we can consider substituting a switch statement for several if-else statements. Performance-wise, switch statements outperform if-else statements. As an example of what to avoid, the following sample is offered below:

Example:

if (cond1) {
    if (cond2) {
        if (cond3 || cond4) {execute ...}


        else {execute.}

Note: Above sample is to be avoided and use this as follows:

Boolean result = (cond1 && cond2) && (cond3 || cond4)

• Avoid Getting the Size of the Collection in the Loop:
  
  Get the collection's size before iterating through any collection; never get it during iterating. As an example of what to avoid, the following sample is offered below:

Illustration with example:

L<String> objL = getDa ();
for (int a = 0; a< objL.size(); a++) {execute code ...}

Note: Above sample is to be avoided and use this as follows:

L<String> objL = getDa ();
int size = objL.size();
for (int a = 0; a< size; a++) {execute code ...}

• Avoid Using String Objects for Concatenation:
  Since a string belongs to the immutable class, any object it creates cannot be reused. Therefore, when we need to create a long string, such as for SQL queries or other uses, it is bad practice to concatenate the String object using the '+' operator. As a result, numerous String objects will be created, which will increase the amount of heap memory used. In this situation, we have the choice of using StringBuilder or StringBuffer, with the former being preferred due to its performance advantage over the latter due to non-synchronized operations. As an example of what to avoid, the following sample is offered below:

String query = String1+String2+String3;

Note: Above sample is to be avoided and use this as follows:

StringBuilder strBuilder = new StringBuilder(“”);


strBuilder.append(String1).append(String2).append(String3);


String query = strBuilder.toString();

• Use Primitive Types Wherever Possible:
  Since primitive type data is saved on stack memory and object data is stored on heap memory, using primitive types over objects is advantageous. Primitive types can be used in place of objects wherever possible since data access from stack memory is quicker than from heap memory. Therefore, using int over Integer or double over Double is always advantageous.

• Avoid Using BigDecimal Class:
  We are aware that the BigDecimal class offers precise accuracy for decimal values. When this object is utilized excessively to calculate values in a loop, the performance is severely hampered. When performing calculations, BigDecimal consumes a lot more memory over long or double. If precision is not a need or if we know the calculated value's range won't go beyond long or double, we can forego using BigDecimal and use long or double with the appropriate casting.

• Avoid Creating Big Objects Often:
  In the application, there are some classes that serve as data bearers. Because of how heavy they are, their creation should be minimised. The DB connection objects, system configuration objects, and session objects for the user after login are a few examples of these items. While being created, these items used a lot of resources.
  The performance of the application would be severely hampered by the generation of these objects due to increased memory utilisation. Wherever possible, we should clone the object rather than producing a new one by using the Singleton technique to build a single instance of the object and reuse it as needed.

• Use Stored Procedures Instead of Queries:
  Instead, then writing intricate and lengthy queries, it is preferable to build stored procedures and use them when processing. Pre-compiled stored procedures are kept in the database as objects. As a query is built and run each time it is called through the application, the execution time of a stored procedure is faster than a query with the same business logic. The stored procedure also reduces data transfer and network traffic because the database server does not need to be transferred with each execution of the complex query.

• Using PreparedStatement instead of Statement:
  To run the SQL query through the program, we use JDBC API and classes. The preparedstatement object offers an advantage over Statement for parameterized query execution because it is only created once and executed several times. On the other hand, a statement object is called repeatedly and compiled before being executed. Additionally, the prepared statement object is secure against SQL injection threats for the security of web applications.

• Use of Unnecessary Log Statements and Incorrect Log Levels:
  Any program must have logging, which must be implemented well to prevent performance hits brought on by improper logging and log levels. Large items shouldn't be logged into code. Logging must be restricted to the parameters we need to keep track of, not the entire object. Additionally, the logging level should remain at a higher level, such as DEBUG or ERROR, rather than INFO. As an example of what to avoid, the following sample is offered below:

Illustration with Example:

Logger.debug("User info: " + user. toString ());
Logger.info ("Method called for setting user data:" + user. getData ());

Note: Above sample is to be avoided and use this as follows:

Logger.debug(“User info: ” + user.getName() + ” : login ID : ” + user.getLoginId());
Logger.info (“Method called for setting user data”);

• Select Required Columns in a Query
  We utilize select queries to retrieve the data while obtaining it from the database. Selecting columns that are not required for additional processing should be avoided. Choose only the columns that we will need for additional processing or for front-end presentation. The database conclusion of the query execution is delayed by selecting an excessive number of columns. Also, it increases network traffic from database to application which should be avoided. The sample is provided below as an illustration which is to be avoided as follows:

select * from users where user_id = 100;

Note: Above sample is to be avoided and use this as follows:

select user_name, user_age, user_gender, user_occupation, user_address from users where user_id = 100;

• Fetch the Data Using Joins
  The right usage of joins on tables is required when retrieving data from various tables. The application's performance will suffer if joins are not used effectively or if the tables are not normalized, which will delay the execution of queries. Subqueries should never be used in place of joins since they execute more slowly. To enhance the efficiency of query execution and lower application latency, create an index on the table's commonly used columns.