{"id":5168,"date":"2021-03-23T11:28:02","date_gmt":"2021-03-23T11:28:02","guid":{"rendered":"https:\/\/ded9.com\/?p=5168"},"modified":"2026-02-17T11:07:48","modified_gmt":"2026-02-17T11:07:48","slug":"30-tips-on-java-programming-and-best-practices-for-beginners","status":"publish","type":"post","link":"https:\/\/ded9.com\/de\/30-tips-on-java-programming-and-best-practices-for-beginners\/","title":{"rendered":"30 Java Programming Tips and Best Practices Every Beginner Should Master"},"content":{"rendered":"

Java is one of the most popular programming languages. Java is used in Windows, web, and mobile applications; network and consumer electronics devices; and configuration boxes. It is ubiquitous.<\/span><\/span><\/p>\n

More than 3 billion devices work with Java; according to Oracle, 5 billion Java cards are in use. More than 9 million developers have chosen Java to write their code, and it is widely used and the most popular Development platform.<\/p>\n

Here are some suggestions on how to look for or get an appointment for Java developers:<\/p>\n

1. Use empty return sets instead of Null.<\/span><\/h2>\n

If the program returns a set with no elements, return an empty set rather than null elements. This causes many “if-else” statements to be removed during null checks.<\/p>\n

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public class getLocationName {\r\n\r\n\u00a0\u00a0\u00a0\u00a0return (null == cityName? \u201c\u201d: cityName);\r\n\r\n}<\/pre>\n<\/div>\n
2- Use the strings carefully.<\/span><\/h2>\n
If two strings are connected in a “for” loop using the “+” operator, a new String object is created in each loop iteration. This wastes memory and increases Runtime. AlRuntimen is building a String prototype; you should avoid the factory and make it directly. For example:<\/p>\n
\n
\/\/ Slower Instantiation\r\n\r\nString bad = new String (\"Yet another string object\");\r\n\r\n\/\/ Faster Instantiation\r\n\r\nString good = \u201cYet another string object\u201d<\/pre>\n<\/div>\n
3. Avoid unnecessary objects.<\/h2>\n
Object Creation is one of Java’s most expensive operations (in terms of memory usage). It is therefore recommended that objects be created or initialized only if necessary. The following code provides an example:<\/p>\n
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import java.util.ArrayList;\r\n\r\nimport java.util.List;\r\n\r\npublic class Employees {\r\n\r\n\u00a0\u00a0\u00a0\u00a0private List Employees;\r\n\r\n\u00a0\u00a0\u00a0\u00a0public List getEmployees () {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ initialize only when required\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0if (null == Employees) {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Employees = new ArrayList ();\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0}\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0return Employees;\r\n\r\n\u00a0\u00a0\u00a0\u00a0}\r\n\r\n}<\/pre>\n<\/div>\n
4- Array between Array and ArrayList<\/span><\/h2>\n
It is often difficult for developers to decide whether to use the ArrayList structure for array data types. Both have strengths and weaknesses, and the choice depends on the requirements.<\/p>\n
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import java.util.ArrayList;\r\n\r\npublic class arrayVsArrayList {\r\n\r\n\u00a0\u00a0\u00a0\u00a0public static void main (String [] args) {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0int [] myArray = new int [6];\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0myArray [7] = 10; \/\/ ArraysOutOfBoundException\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ Declaration of ArrayList. Add and Remove of elements is easy.\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0ArrayList <Integer> myArrayList = new ArrayList <> ();\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0myArrayList.add (1);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0myArrayList.add (2);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0myArrayList.add (3);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0myArrayList.add (4);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0myArrayList.add (5);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0myArrayList.remove (0);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0for (int i = 0; i <myArrayList.size (); i ++) {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0System.out.println (\u201cElement:\u201d + myArrayList.get (i));\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0}\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ Multi-dimensional Array\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0int [] [] [] multiArray = new int [3] [3] [3];\r\n\r\n\u00a0\u00a0\u00a0\u00a0}\r\n\r\n}<\/pre>\n<\/div>\n
1- Arrays have a fixed size, but the size varies in ArrayLists. Because the array size is constant, memory is allocated for the array type variable at declaration and initialization.<\/p>\n
As a result, arrays are high-speed.<\/p>\n
On the other hand, if the data size is unknown, using an array with more capacity avoids index errors that exceed the array size and reduces wasted storage space.<\/p>\n
2- Adding or removing elements from an ArrayList is much easier than from an array.<\/p>\n
3- An Array can be multidimensional, but an ArrayList can only have one dimension.<\/p>\n
5. When does the finally code not run, try?<\/span><\/h2>\n
Consider the following code snippet:<\/p>\n
\n
public class shutDownHooksDemo {\r\n\r\n\u00a0\u00a0\u00a0\u00a0public static void main (String [] args) {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0for (int i = 0; i <5; i ++)\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0{\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0try {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0if (i == 4) {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0System.out.println (\u201cInside Try Block.Exiting without executing Finally block.\u201d);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0System.exit (0);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0}\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0}\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0finally {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0System.out.println (\u201cInside Finally Block.\u201d);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0}\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0}\r\n\r\n\u00a0\u00a0\u00a0\u00a0}\r\n\r\n}<\/pre>\n<\/div>\n
In the above program, it appears that “println” is executed five times in the finally block. However, when running the program, the user notices that the finally block is called only four times.<\/p>\n
In the fifth iteration, the exit function is called once and then never called again.<\/p>\n
This is because running the System. The exit function stops all running threads, including the current stream. Executing the exit statement does not perform the finally block after the Try.<\/p>\n
W Try System. Exit Trycalled, the JVM performs two cleanup tasks before stopping the program:<\/p>\n