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Java Switch Statement is fall-through:

The Java switch statement is fall-through if a break statement is not present that's means it executes all statements after the first match. Example:

Decision Making Java Switch Statement

The Java switch statement executes one statement from multiple conditions. It is like an if-else-if ladder statement. The switch statement tests the equality of a variable against multiple values. Example:

Java Nested if statement

Generally, if condition works like yes or no. If the condition satisfies, it executes, Otherwise it doesn’t execute the code.
Nested if condition means if-within-if. Nested if condition comes under decision-making statement in Java. There could be infinite if conditions inside an if condition.
Example:

Decision Making : If-else-If ladder
Java if-else-if ladder is used to decide among multiple options. In other words, it is the chain of if-else statements that create a decision tree. We can also define an else statement at the end of the chain.
Syntax: if(condition 1) {statement 1; //executes when condition 1 is true}
else if(condition 2) {statement 2; //executes when condition 2 is true}
else {statement 2; //executes when all the conditions are false}

Example:

Decision Making : If-else statement
As you see, in ‘if statement’ that condition true then program will run and condition false program will not execute. But, if condition false and even then program run, then 'if-else statement’ comes to the picture.
Syntax: if(condition){statement 1; //executes when condition is true}
else{statement 2; //executes when condition is false}
Ex:

Decision Making – If statement
The Java if statement is the most simple decision-making statement. It is used to decide whether a certain statement or block of statements will be executed or not that is, if a certain condition is true then a block of statement is executed otherwise will not execute.
Syntax: if (condition) {statement; //execute when condition True}

Decision-Making statements:
Decision making statements allow you to decide the order of ex*****on of specific statements in your program. There are two types of decision-making statements in Java, i.e., If statement and switch statement.

Java Control Statements

Java Keywords:
Java keywords are reserved words. Java keywords are particular words that act as a code. These are predefined words by Java so they cannot be used as a variable or object name or class name.

Apache Log4j: The least you need to know right now:
There is a vulnerability in Apache Log4j starting with version 2.0 released July 2014
This vulnerability is actively being exploited in the wild
Exploiting this vulnerability allows remote code ex*****on (RCE)
This vulnerability is trivial to exploit.
There is a patch available and you should patch immediately.
A configuration change may also mitigate the vulnerability (if you can’t patch)
To protect your systems, you need to know what is affected.