> For the complete documentation index, see [llms.txt](https://www.pranaypourkar.co.in/the-programmers-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.pranaypourkar.co.in/the-programmers-guide/java/java-basics/java-data-types.md).

# Java Data Types

In Java, data types specify the size and type of values that can be stored in variables. Java has two categories of data types: **Primitive** data types and **Reference** data types.

## **Primitive D**ata Type

Primitive data types are predefined by the language and are named by a reserved keyword. They represent single values and are not objects.

### Different Types

<table data-full-width="true"><thead><tr><th>Data Type</th><th>Description</th><th>Size</th><th>Default Value</th></tr></thead><tbody><tr><td><code>byte</code></td><td>8-bit signed integer</td><td>1 byte</td><td>0</td></tr><tr><td><code>short</code></td><td>16-bit signed integer</td><td>2 bytes</td><td>0</td></tr><tr><td><code>int</code></td><td>32-bit signed integer</td><td>4 bytes</td><td>0</td></tr><tr><td><code>long</code></td><td>64-bit signed integer</td><td>8 bytes</td><td>0L</td></tr><tr><td><code>float</code></td><td>32-bit floating point</td><td>4 bytes</td><td>0.0f</td></tr><tr><td><code>double</code></td><td>64-bit floating point</td><td>8 bytes</td><td>0.0d</td></tr><tr><td><code>char</code></td><td>16-bit Unicode character</td><td>2 bytes</td><td>'\u0000'</td></tr><tr><td><code>boolean</code></td><td>true or false</td><td>not precisely defined</td><td>false</td></tr></tbody></table>

### Limits or Range

| Data Type | Size (in bits)        | Minimum Value                          | Maximum Value                           |
| --------- | --------------------- | -------------------------------------- | --------------------------------------- |
| `byte`    | 8                     | -128                                   | 127                                     |
| `short`   | 16                    | -32,768                                | 32,767                                  |
| `int`     | 32                    | -2,147,483,648                         | 2,147,483,647                           |
| `long`    | 64                    | -9,223,372,036,854,775,808             | 9,223,372,036,854,775,807               |
| `float`   | 32                    | Approximately ±3.40282347E+38F         | Approximately ±1.40239846E-45F          |
| `double`  | 64                    | Approximately ±1.7976931348623157E+308 | Approximately ±4.94065645841246544E-324 |
| `char`    | 16                    | 0                                      | 65,535                                  |
| `boolean` | not precisely defined | true or false                          | true or false                           |

{% hint style="info" %}
Size of data types is constant in java. The JVM (Java Virtual Machine) is designed to be platform independent. If data type sizes were different across platforms, then cross-platform consistency is sacrificed. The JVM isolates the program from the underlying OS and platform.
{% endhint %}

## Reference Data Types:

Reference data types are objects that hold references to the memory location where the data is stored. They include classes, interfaces, arrays, and enumerations.

### **Primitive Wrapper Classes:**

These are reference data types that wrap primitive data types into objects. For example:

* `Byte`
* `Short`
* `Integer`
* `Long`
* `Float`
* `Double`
* `Character`
* `Boolean`

These wrapper classes are useful when working with collections or when you need to treat primitive types as objects.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://www.pranaypourkar.co.in/the-programmers-guide/java/java-basics/java-data-types.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.