String comparison in Java - Step-by-Step Execution

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Concept Flow - String comparison

Start

↓

Create two strings

↓

Compare strings using equals()

↓

If true

→Print "Strings are equal"

↓

If false

→Print "Strings are not equal"

↓

Compare strings using ==

↓

If true

→Print "References are equal"

↓

If false

→Print "References are not equal"

↓

End

This flow shows creating two strings, comparing their content with equals(), then comparing their references with ==, and printing results accordingly.

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Execution Sample

Java

String s1 = new String("hello");
String s2 = new String("hello");
if (s1.equals(s2)) {
    System.out.println("Strings are equal");
} else {
    System.out.println("Strings are not equal");
}
if (s1 == s2) {
    System.out.println("References are equal");
} else {
    System.out.println("References are not equal");
}

This code compares two different String objects with the same content using equals() and ==, printing the results.

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Execution Table

Step	Action	Evaluation	Result	Output
1	Create s1	s1 = new String("hello")	s1 points to new String object with "hello"
2	Create s2	s2 = new String("hello")	s2 points to different new String object with "hello"
3	Compare s1.equals(s2)	s1.equals(s2) checks content equality	true	Strings are equal
4	Compare s1 == s2	s1 == s2 checks reference equality	false	References are not equal
5	End	No more code

💡 Execution stops after printing both comparison results.

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Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
s1	null	Reference to String object "hello"	Reference to String object "hello"	Reference to String object "hello"
s2	null	null	Reference to different String object "hello"	Reference to different String object "hello"

key

Key Moments - 2 Insights

▶Why does s1.equals(s2) return true but s1 == s2 return false?

▶What would happen if we used String s1 = "hello"; and String s2 = "hello"; instead?

psychology

Visual Quiz - 3 Questions

Look at the execution table, what is the result of s1.equals(s2) at step 3?

A false

B true

C null

D throws error

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Concept Snapshot

String comparison in Java:
- Use equals() to compare text content.
- Use == to compare if two variables point to the same object.
- new String() creates new objects, so == is usually false.
- String literals may share references, making == true.
- Always use equals() to check string equality.

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Full Transcript

This example shows how Java compares strings. Two strings s1 and s2 are created with the same text but as different objects. Using equals() compares their text and returns true, so the program prints "Strings are equal". Using == compares if they are the same object, which they are not, so it prints "References are not equal". This teaches that equals() checks content, while == checks references. If s2 was assigned s1, then both would point to the same object and both comparisons would be true.