Stages of Software Development Lifecycle using a waterfall approach In the waterfall approach, each stage of the project delivered is a set of tasks that have to be completed by a planned deadline. A common set of stages for a software development project are [1]: System requirements Software requirements Analysis Program design Coding Testing Operations (until the system reaches its end of life - EOL) In theory, after the requirements are gathered, and the system was designed, implementation has to satisfy the requirements and the design without the possibility of changing the agreements made during in previous phases. Each phase is a silo of work, which is disconnected from other silos . This can result in a situation of conflicting requirements being detected during the testing or deployment phase without a chance to discuss these requirements with their authors. Maintenance is a special type of stage because there are cases when it is unknown, how long the system will be...
Which Java version understands the var keyword?
In order to use the var keyword, you must use a project based on Java 10. It is the first Java version that has introduced this keyword.
How can the var keyword be used?
The formal name of this keyword is local variable type inference [1]. If we take a closer look at this name, we can recognize that it is composed of two parts: "local variable" and "type inference".
Why could you use type inference?
The juicy part of the local variable type inference is the type inference part, which practically means, that Java will assume the type of the variable, removing the need to explicitly write the type of the variable.
It can reduce the number of keystrokes that are necessary to write our program by a significant amount and eliminate the possibility of making a typo. For example, instead of writing ArrayList<ObservableClassName>, we can write only 3 letters: var.
Where var cannot be used as of Java 10?
It cannot be used in the instance variables, which are another type of variable than local variables. Simply put, local variables are non-static variables that are defined in a block of executable code. On the other hand, instance variables are defined as non-static variables which are outside any block of executable code.
Here, I have a question for you ;) Is keyword var allowed in the method parameters? For example, in this case?:
public int addTwoVariables(var a, var b) {return a + b;}
Will it compile?
What if I use var to declare an instance variable?
Then, the compiler will show you an error:
'var' is not allowed here
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Sources list:
[1] Oracle® Certified Professional Java SE 17 Developer, by Scott Selikoff and Jeanne Boyarsky
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