Control Statements in Java:

• Control Statements in Java is one of the fundamentals required for Java Programming. It allows the smooth flow of a program.
• Java compiler executes the code from top to bottom.
• The statements in the code are executed according to the order in which they appear.
• However, Java provides statements that can be used to control the flow of Java code.
• Such statements are called control flow statements.

Different types of Control Statements:

• Decision Making Statements:
  • if statements
  • switch statement
• Loop Statements:
  • do while loop
  • while loop
  • for loop
  • for-each loop
• Jump Statements:
  • break statement
  • continue statement

https://www.w3adda.com/java-tutorial/java-control-flow-statements

Decision-Making statements:

• Decision-making statements decide which statement to execute and when.
• Decision-making statements evaluate the Boolean expression and control the program flow depending upon the result of the condition provided.
• There are two types of decision-making statements in Java, i.e., If statement and switch statement.

https://data-flair.training/blogs/decision-making-in-java/

1) If Statement:

• In Java, the “if” statement is used to evaluate a condition.
• The control of the program is diverted depending upon the specific condition.
• The condition of the If statement gives a Boolean value, either true or false.
• In Java, there are four types of if-statements given below.

https://www.programiz.com/java-programming/if-else-statement

public class IfExample {  
public static void main(String[] args) {  
    //defining an 'age' variable  
    int age=20;  
    //checking the age  
    if(age>18){  
        System.out.print("Age is greater than 18");  
    }  
}  
}

2) if-else statement

• The if -else statement is an extension to the if-statement, which uses another block of code, i.e., else block.
• The else block is executed if the condition of the if-block is evaluated as false.
• The if -else statement is an extension to the if-statement, which uses another block of code, i.e., else block.
• The else block is executed if the condition of the if-block is evaluated as false.

https://www.javatpoint.com/java-if-else

public class Student {  
public static void main(String[] args) {  
int x = 10;  
int y = 12;  
if(x+y < 10) 
{  
System.out.println("x + y is less than 10");  
}   
else 
{  
System.out.println("x + y is greater than 20");  
}  
}  
}

3) if-else-if ladder:

• The if-else-if statement contains the if-statement followed by multiple else-if statements.
• In other words, we can say that it is the chain of if-else statements that create a decision tree where the program may enter in the block of code where the condition is true.
• We can also define an else statement at the end of the chain.

https://www.geeksforgeeks.org/java-if-else-if-ladder-with-examples/

public class Student 
{  
public static void main(String[] args) 
{  
String city = "Pudukkottai";  
if(city == "Madurai") 
{  
System.out.println("City is Madurai");  
}
else if (city == "Trichy") 
{  
System.out.println("City is Trichy");  
}
else if(city == "Karaikudi") 
{  
System.out.println("City is Karaikudi");  
}
else 
{  
System.out.println(city);  
}  
}  
}  

4. Nested if-statement

In nested if-statements, the if statement can contain a if or if-else statement inside another if or else-if statement.

https://www.educba.com/nested-if-statements-in-java/

public class JavaNestedIfExample 
{    
public static void main(String[] args) 
{                 //Creating two variables for age and weight  
int age=20;  
int weight=80;    //applying condition on age and weight  
if(age>=18)
{    
if(weight>50)
{  
System.out.println("You are eligible to donate blood");  
}    
}    
}
}

Reference:

https://www.javatpoint.com/control-flow-in-java

https://www.geeksforgeeks.org/decision-making-javaif-else-switch-break-continue-jump/