Quick Answer
The valid switch expression types in Java 8 are `int`, `char`, and `String`. This is correct because the switch statement compiles to either a `tableswitch` or `lookupswitch` bytecode instruction, which relies on integer-based keys; `char` and `int` are integral primitives that map directly to these keys, while `String` was added in Java 7 by converting its hash code to an integer for comparison. On the Oracle Java Foundations 1Z0-811 exam, this question tests your understanding of the limited type set available before Java 14 expanded switch expressions, and a common trap is assuming `long` or `boolean` are allowed—`long` is too large for the bytecode instructions, and `boolean` has only two values, making it unsuitable for multi-branch logic. To remember, think of the mnemonic "ICS" for int, char, and String—the only three types that work in a Java 8 switch.
This 1Z0-811 practice question tests your understanding of control flow and loops. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE of the following are valid types that can be used as a switch expression in Java (as of Java 8)?
long
Why wrong: long is not allowed; only int and smaller integer types.
String
String is valid since Java 7.
char
char is a valid switch type.
int
int is a valid switch type.
boolean
Why wrong: boolean is not allowed in switch.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
String
In Java 8, a switch expression can use `String`, `char`, and `int` as valid types. `String` was added in Java 7, and `char` and `int` are among the original primitive types supported. `long` and `boolean` are not allowed because `long` is a 64-bit type not supported by the switch statement's underlying `tableswitch` or `lookupswitch` bytecode instructions, and `boolean` has only two values, making it unsuitable for switch's multi-branch logic.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
long
Why it's wrong here
long is not allowed; only int and smaller integer types.
String
Why this is correct
String is valid since Java 7.
Related concept
Read the scenario before looking for a memorised answer.
char
Why this is correct
char is a valid switch type.
Related concept
Read the scenario before looking for a memorised answer.
int
Why this is correct
int is a valid switch type.
Related concept
Read the scenario before looking for a memorised answer.
boolean
Why it's wrong here
boolean is not allowed in switch.
Common exam traps
Cisco often tests the misconception that `long` is a valid switch type because it is a numeric primitive, but the JVM's switch bytecode only supports 32-bit integer types, making `long` invalid.
Detailed technical explanation
Under the hood, the Java compiler translates switch statements on `int` (and smaller integer types) into `tableswitch` or `lookupswitch` bytecode instructions, which operate on 32-bit integer keys. For `String`, the compiler computes the hash code of the string and uses an inner switch on an `int`, then performs additional `equals()` checks to handle collisions. This is why `long` (64-bit) is excluded—it would require a different bytecode mechanism not present in the JVM specification.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the 1Z0-811 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
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FAQ
Control Flow and Loops — This question tests Control Flow and Loops — Read the scenario before looking for a memorised answer..
The correct answer is: String — In Java 8, a switch expression can use `String`, `char`, and `int` as valid types. `String` was added in Java 7, and `char` and `int` are among the original primitive types supported. `long` and `boolean` are not allowed because `long` is a 64-bit type not supported by the switch statement's underlying `tableswitch` or `lookupswitch` bytecode instructions, and `boolean` has only two values, making it unsuitable for switch's multi-branch logic.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
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