In EL (${ ... }), you can use many types of operators — very similar to Java, but slightly simplified.

Here’s the full organized list:

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🔵 1. Arithmetic Operators

Operator	Description	Example
+	Addition	${2 + 3} → 5
-	Subtraction	${5 - 2} → 3
*	Multiplication	${4 * 2} → 8
/ or div	Division	${10 / 2} or ${10 div 2} → 5
% or mod	Modulus (remainder)	${10 % 3} or ${10 mod 3} → 1

✅ div and mod are alternative keywords for / and % (useful when writing XML-compliant EL inside XHTML).

🔵 2. Relational (Comparison) Operators

Operator	Description	Example
== or eq	Equal to	${5 == 5} or ${5 eq 5} → true
!= or ne	Not equal to	${5 != 3} or ${5 ne 3} → true
< or lt	Less than	${3 < 5} or ${3 lt 5} → true
> or gt	Greater than	${5 > 3} or ${5 gt 3} → true
<= or le	Less than or equal to	${5 <= 5} or ${5 le 5} → true
>= or ge	Greater than or equal to	${5 >= 3} or ${5 ge 3} → true

✅ Again, the text forms like eq, lt, gt are XML-friendly.

🔵 3. Logical Operators

Operator	Description	Example
&& or and	Logical AND	${(5 > 2) && (3 < 4)} or ${(5 gt 2) and (3 lt 4)} → true
`		oror`
! or not	Logical NOT	${!(5 > 6)} or ${not (5 gt 6)} → true

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🔵 4. Empty Operator

Operator	Description	Example
empty	Checks if a value is null, empty string, empty collection, or empty array	${empty userList}

✅ If userList is null or empty, empty userList returns true.

Very useful for checking nulls safely!

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🔵 5. Conditional Operator (Ternary)

Just like Java’s ? : operator.

Syntax	Example
condition ? valueIfTrue : valueIfFalse	${(age > 18) ? 'Adult' : 'Minor'}

✅ Simple way to make decisions inside EL.

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🎯 Final Full List:

Operator Type	Examples
Arithmetic	+, -, *, / (div), % (mod)
Relational (Comparison)	==, !=, <, >, <=, >= (eq, ne, lt, gt, le, ge)
Logical	&&, `
Empty Test	empty
Conditional (Ternary)	condition ? value1 : value2

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📢 Important Notes:

• EL is null-safe. If you reference something that doesn’t exist, it won’t throw an exception — it simply treats it as empty or null.
• Word operators (eq, lt, and, etc.) are mainly there to be XML-compliant (some HTML parsers break on < or > symbols).

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🚀 Super Quick Example Mixing Them:

<c:if test="${not empty user and user.age gt 18}">
    <p>Welcome, ${user.name}! You are an adult.</p>
</c:if>

Checks if user exists and is older than 18.

Greets the user if conditions are met.