3) What is JIT compiler?
Just-In-Time(JIT) compiler:It is used to improve the performance. JIT compiles parts of the byte code that have similar functionality at the same time, and hence reduces the amount of time needed for compilation. Here the term “compiler” refers to a translator from the instruction set of a Java virtual machine (JVM) to the instruction set of a specific CPU.
@javaCode☕️
Just-In-Time(JIT) compiler:It is used to improve the performance. JIT compiles parts of the byte code that have similar functionality at the same time, and hence reduces the amount of time needed for compilation. Here the term “compiler” refers to a translator from the instruction set of a Java virtual machine (JVM) to the instruction set of a specific CPU.
@javaCode☕️
What Is Refactoring?
Refactoring is the process of changing a software system in such a way that it does not alter the external behavior of the code yet improves its internal structure. It is a disciplined way to clean up code that minimizes the chances of introducing bugs. In essence when you refactor you are improving the design of the code after it has been written.
@javaCode☕️
Refactoring is the process of changing a software system in such a way that it does not alter the external behavior of the code yet improves its internal structure. It is a disciplined way to clean up code that minimizes the chances of introducing bugs. In essence when you refactor you are improving the design of the code after it has been written.
@javaCode☕️
4) What is platform?
A platform is basically the hardware or software environment in which a program runs. There are two types of platforms software-based and hardware-based. Java provides software-based platform.
@javaCode☕️
A platform is basically the hardware or software environment in which a program runs. There are two types of platforms software-based and hardware-based. Java provides software-based platform.
@javaCode☕️
👍1
#Refactoring
Lesson 2:
Bloaters
Bloaters are code, methods and classes that have increased to such gargantuan proportions that they are hard to work with. Usually these smells do not crop up right away, rather they accumulate over time as the program evolves (and especially when nobody makes an effort to eradicate them).
1. Long Method
2. Large Class
3. Primitive Obsession
4. Long Parameter List
5. Data Clumps
@javaCode☕️
Lesson 2:
Bloaters
Bloaters are code, methods and classes that have increased to such gargantuan proportions that they are hard to work with. Usually these smells do not crop up right away, rather they accumulate over time as the program evolves (and especially when nobody makes an effort to eradicate them).
1. Long Method
2. Large Class
3. Primitive Obsession
4. Long Parameter List
5. Data Clumps
@javaCode☕️
#Java_Interview_Question :
5) What is the main difference between Java platform and other platforms?
The Java platform differs from most other platforms in the sense that it's a software-based platform that runs on top of other hardware-based platforms. It has two components:
Runtime Environment
API(Application Programming Interface)
@javaCode☕️
5) What is the main difference between Java platform and other platforms?
The Java platform differs from most other platforms in the sense that it's a software-based platform that runs on top of other hardware-based platforms. It has two components:
Runtime Environment
API(Application Programming Interface)
@javaCode☕️
#Java_Interview_Question :
6) What gives Java its 'write once and run anywhere' nature?
The bytecode. Java is compiled to be a byte code which is the intermediate language between source code and machine code. This byte code is not platform specific and hence can be fed to any platform.
@javaCode☕️
6) What gives Java its 'write once and run anywhere' nature?
The bytecode. Java is compiled to be a byte code which is the intermediate language between source code and machine code. This byte code is not platform specific and hence can be fed to any platform.
@javaCode☕️
#Refactoring
Lesson 3:
Long Method
📌Signs and Symptoms📌
A method contains too many lines of code. Generally, any method longer than ten lines should make you start asking questions.
📌Reasons for the Problem📌
Like the Hotel California, something is always being added to a method but nothing is ever taken out. Since it is easier to write code than to read it, this "smell" remains unnoticed until the method turns into an ugly, oversized beast.
Mentally, it is often harder to create a new method than to add to an existing one: "But it's just two lines, there's no use in creating a whole method just for that..." Which means that another line is added and then yet another, giving birth to a tangle of spaghetti code.
@javaCode☕️
Lesson 3:
Long Method
📌Signs and Symptoms📌
A method contains too many lines of code. Generally, any method longer than ten lines should make you start asking questions.
📌Reasons for the Problem📌
Like the Hotel California, something is always being added to a method but nothing is ever taken out. Since it is easier to write code than to read it, this "smell" remains unnoticed until the method turns into an ugly, oversized beast.
Mentally, it is often harder to create a new method than to add to an existing one: "But it's just two lines, there's no use in creating a whole method just for that..." Which means that another line is added and then yet another, giving birth to a tangle of spaghetti code.
@javaCode☕️
☕️JAVA Language Community
Treatment for Long Method @javaCode☕️
📌Treatment📌
As a rule of thumb, if you feel the need to comment on something inside a method, you should take this code and put it in a new method. Even a single line can and should be split off into a separate method, if it requires explanations. And if the method has a descriptive name, nobody will need to look at the code to see what it does.
1. To reduce the length of a method body, use Extract Method.
2. If local variables and parameters interfere with extracting a method, use Replace Temp with Query, Introduce Parameter Object or Preserve Whole Object.
3. If none of the previous recipes help, try moving the entire method to a separate object via Replace Method with Method Object.
4. Conditional operators and loops are a good clue that code can be moved to a separate method. For conditionals, use Decompose Conditional. If loops are in the way, try Extract Method.
@javaCode☕️
As a rule of thumb, if you feel the need to comment on something inside a method, you should take this code and put it in a new method. Even a single line can and should be split off into a separate method, if it requires explanations. And if the method has a descriptive name, nobody will need to look at the code to see what it does.
1. To reduce the length of a method body, use Extract Method.
2. If local variables and parameters interfere with extracting a method, use Replace Temp with Query, Introduce Parameter Object or Preserve Whole Object.
3. If none of the previous recipes help, try moving the entire method to a separate object via Replace Method with Method Object.
4. Conditional operators and loops are a good clue that code can be moved to a separate method. For conditionals, use Decompose Conditional. If loops are in the way, try Extract Method.
@javaCode☕️
#Java_Interview_Question
7) What is classloader?
The classloader is a subsystem of JVM that is used to load classes and interfaces.There are many types of classloaders e.g. Bootstrap classloader, Extension classloader, System classloader, Plugin classloader etc.
@javaCode☕️
7) What is classloader?
The classloader is a subsystem of JVM that is used to load classes and interfaces.There are many types of classloaders e.g. Bootstrap classloader, Extension classloader, System classloader, Plugin classloader etc.
@javaCode☕️
#Java_Interview_Question
8) Is Empty .java file name a valid source file name?
Yes, save your java file by .java only, compile it by javac .java and run by java yourclassname Let's take a simple example:
//save by .java only
class A{
public static void main(String args[]){
System.out.println("Hello java");
}
}
//compile by javac .java
//run by java A
compile it by javac .java
run it by java A
@javaCode☕️
8) Is Empty .java file name a valid source file name?
Yes, save your java file by .java only, compile it by javac .java and run by java yourclassname Let's take a simple example:
//save by .java only
class A{
public static void main(String args[]){
System.out.println("Hello java");
}
}
//compile by javac .java
//run by java A
compile it by javac .java
run it by java A
@javaCode☕️
#Java_Interview_Question
10) If I don't provide any arguments on the command line, then the String array of Main method will be empty or null?
It is empty. But not null.
@javaCode☕️
10) If I don't provide any arguments on the command line, then the String array of Main method will be empty or null?
It is empty. But not null.
@javaCode☕️
#Design_Patterns
Design Patterns:
In software engineering, a design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern isn't a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations.
@javaCode☕️
Design Patterns:
In software engineering, a design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern isn't a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations.
@javaCode☕️
#Design_Patterns
Uses of Design Patterns
Design patterns can speed up the development process by providing tested, proven development paradigms. Effective software design requires considering issues that may not become visible until later in the implementation. Reusing design patterns helps to prevent subtle issues that can cause major problems and improves code readability for coders and architects familiar with the patterns.
Often, people only understand how to apply certain software design techniques to certain problems. These techniques are difficult to apply to a broader range of problems. Design patterns provide general solutions, documented in a format that doesn't require specifics tied to a particular problem.
In addition, patterns allow developers to communicate using well-known, well understood names for software interactions. Common design patterns can be improved over time, making them more robust than ad-hoc designs.
@javaCode☕️
Uses of Design Patterns
Design patterns can speed up the development process by providing tested, proven development paradigms. Effective software design requires considering issues that may not become visible until later in the implementation. Reusing design patterns helps to prevent subtle issues that can cause major problems and improves code readability for coders and architects familiar with the patterns.
Often, people only understand how to apply certain software design techniques to certain problems. These techniques are difficult to apply to a broader range of problems. Design patterns provide general solutions, documented in a format that doesn't require specifics tied to a particular problem.
In addition, patterns allow developers to communicate using well-known, well understood names for software interactions. Common design patterns can be improved over time, making them more robust than ad-hoc designs.
@javaCode☕️
#Java_Interview_Question
11) What if I write static public void instead of public static void?
Program compiles and runs properly.
@javaCode☕️
11) What if I write static public void instead of public static void?
Program compiles and runs properly.
@javaCode☕️
#Java_Interview_Question
12) What is the default value of the local variables?
The local variables are not initialized to any default value, neither primitives nor object references.
@javaCode☕️
12) What is the default value of the local variables?
The local variables are not initialized to any default value, neither primitives nor object references.
@javaCode☕️