In Java, truncation refers to the process of discarding the fractional part of a number, usually during type conversion from a type with a larger range or precision to a type with a smaller range or precision. This often occurs when converting a floating-point number to an integer type. Here are some examples and explanations:

1. **Floating-Point to Integer Conversion: **When a floating-point number is cast to an integer in Java, truncation occurs—the fractional part of the number is discarded, and only the whole part is kept.

```java
float f = 4.75f;
int i = (int) f; // i is now 4, as the fractional part .75 is truncated
```

2. **Implicit Truncation:**

Truncation can also occur implicitly in some situations. For instance, when performing integer division, the result is truncated.

```java
int result = 7 / 3; // result is 2, as the fractional part .333 is truncated
```

3. **Avoiding Truncation:**

If you want to avoid truncation, you may need to use a type that can hold the value without loss of precision, or use rounding instead of truncation. For rounding, you can use the `Math.round()` method:

```java
float f = 4.75f;
int i = Math.round(f); // i is now 5
```

Truncation is a fundamental concept that comes into play when dealing with numerical data types and conversions in Java. Being aware of when truncation occurs, and how it may affect your calculations, is important for writing accurate and reliable Java programs.