35 Java Programming Tips And Best Practices For Beginners

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Java is claimed to be used in more than 3 billion devices and according to Oracle, there are 5 billion active Java cards in the world today. This means Java is everywhere, literally. Let’s look at some of the best tips for you to join the 9M+ programmers using it every day.

These are some simple tips to get started with JAVA on your own. Don’t panic if you have a hard time with them, you can always hire a consultant professional as a freelancer at www.freelancer.com to correct your lines and make your programming perfect.

1. Trace your codes on paper

If you are a complete beginner, the only way to closely follow up on trial and error is by writing it down.

2. Practice in a safe environment

In order to make your mistakes (you’re going to make plenty, believe me) and not destroy anything valuable, practicing in a safe environment is a must. Check here for the basics.

3. Plan the needed objects before you start

Always keep object requirements under check so you don’t create unwanted or unnecessary objects in the code. Remember that every object you create takes memory and processor resources from the system.

4. Avoid the most expensive unnecessary objects first

You have “cheap” and “expensive” operations; this is exactly why it is important Objects are created or initialized if needed. When in doubt, always go for the cheapest.

5. Solving the dilemma; should you use ArrayList or Array?

This choice depends on your requirements. Let´s see some differences in each:

  • It’s easier to remove or add elements from ArrayList than Array.

  • ArrayList can be only one dimension, while an Array can be multi-dimensional

  • ArrayLists have variable sizes, while Arrays have a fixed size.

6. The moment Finally isn’t executed with Try

JVM performs two clear-out tasks before turning off.

  • First, it goes for all the Shutdown hooks registered. It releases the resources to JVM and because of it this, it is very useful.

  • Second, the finalizers. They have been belittled for a long time since they can run on live objects when manipulated by other threads. This ends in undesirable results, or even in a deadlock.

7. Oddity not allowed

Considering Negative Odd Numbers is always a must when you put together your lines, otherwise you will end up with a false result returned, which is incorrect.

8. Quotes, make it a Double?

Whenever you use double quotes, characters are treated as a string. Simple quotes convert to int values through a process known as widening primitive conversion.

9. Memory leaks can be avoided by implementing these simple tricks

Memory leaks often cause the degradation of the software they compose. There are some standard techniques to prevent memory leakage, even though Java manages memory automatically and doesn’t leave much room for programmers to tinker with it.

  • Always release database connections (when querying is complete).

  • Final block is a must whenever possible.

  • The instances which are stored in Static Tables should always be released.

10. No more Deadlocks

When do they occur? Deadlocks are very common and can happen for diverse reasons. While there’s no definitive process for avoiding deadlocks, they normally follow when one synchronized object is waiting for the latch resources that are locked by another synchronized object.

  • Beware of resources locking!

11. Java needs memory, reserve it!

A proper command line can be auxiliary to preserve RAM for high-demanding. Some of the characters to be used are:

  • XX:PermSize = This is the initial size owed during startup of the JVM.

  • Xms = Minimum memory provision pool.

  • XX:MaxPermSize = This is the maximum scope allocated during startup of the JVM.

  • Xmx = Maximum memory provision pool.

12. Can operations be timed in Java?

The time processes in Java have two main formats. Is there a better one to be used? It depends on the circumstances; basically System.nanoTime() is always faster.

13. Should I choose Double or Float?

Double offers far more accuracy, and most processors take the same quantity of processing interval to perform both kinds of procedures. Go for Double whenever possible.

14. The calculation of power

You should always use Multiplication since it is 300-600 times faster.

15. Null Pointer Exceptions treatment

The trick to avoid this collective exclusion is to check Nulls prematurely. This is  so they can be eliminated, and you don’t call any method upon them.

16. Always encode using JSON

This is becoming increasingly widespread due to being extremely light-weight. An ordinary data structure can be programmed in JSON and effortlessly shared all along the pages.

17. Before decoding from JSON

Before doing this, you should be aware of the schema.

18. Searching for the missing Simple String

Java will return the position of index of the desired String Object. When missing, it comes back as -1.

19. How to list the content of a directory

A program can be used to list the insides of a directory. It will simply obtain all the titles, of all the sub-directory and files in an Array.

20. As simple as a Simple IO

Used to read and write a file, this service can generate input and output streams. It is vital to close the streams when the file management is done.

21. Shell Command execution within the Java environment

For running them, Java offers Runtime Class. These are external commands and the exemptions should be handled cautiously, because they are very important.

22. The use of Regex

This is a summary of the most popular expression constructs regularly used that can be found here.

23. Java´s Simple Swing

Javax, Swing and GUI can be created with Java’s help. Components like Button, Text Box, Radio Button, etc. are GUI mechanisms. They can be accompaniments to Boxes and should go on top of the Container.

24. Java, the sound player

This is a feature that´s especially popular when playing games. Audio files can be played along with JAVA codes.

25. Exporting PDF files from Java

Using itextpdf makes it a lot easier to export PDF. You should try it, since transferring a table to PDF is a very common requirement in Java programs.

26. Email anyone from the Java Code

You need to install Java Mail Jar and set its route in your program’s classpath. It is very simple, because the elementary properties are set in the code.

27. Time measurements

Java offers two static approaches in static class:

  • currentTimeMillis(): Shows current interval in milliseconds.

  • nanoTime(): Returns the current value in nanoseconds.

28. Rescaling an Image

This can be achieved using AffineTransform. It will buffer the original and then render the scaled one.

29. Can the mouse hove coordinates be captured?

This is attained by applying MouseMotionListner Interface. It activates when the mouse is hovered over a specific section.

29. What’s the use of File Output Stream vs. the use of File Writer?

If you are attempting to write streams of characters, think about using File Writer. For everything related to raw bytes (like image data), you should go with File Output Stream, because it was created for that.

30. Primitive classes are preferred over Wrapper Class

Primitive classes are faster.

32. Always favor returning Empty Collections rather than Null

We always prefer this outcome. It will help you avoid a lot of “if else” testing on those Null ones.

33. Use the Strings very carefully

You create a new String Object every time two Strings are concatenated by “+” functioning in a “for” loop, growing performance time and producing memory depletion. Added to this, you should always evade constructors when instantiating a String Object. It should occur directly.

34. Always validate all input sources

From all untrusted data sources, no exceptions! If this step is done properly, you can eradicate virtually all vulnerabilities from that specific software. External data sources may include: network interfaces, command line arguments, environmental variables and user controlled files.

35. Default deny

Everything is guilty before proven innocent. This means that access is denied by default, and the defense scheme recognizes conditions under which admission is allowed.

Did we leave any incredible tip out? What would you add to this list? Leave us a comment below!

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Đã đăng 11 tháng 8, 2017

LucyKarinsky
LucyKarinsky Nhân viên

Software Developer

Lucy is the Development & Programming Correspondent for Freelancer.com. She is currently based in Sydney.

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