Java generic type erasure principle: During compilation, generic type information will be eliminated, leaving only the type-erased bytecode to improve efficiency and compatibility. Application scenarios include reusable code, type safety, and common data structures. However, please note the limitations of type conversion, the inability of reflection to obtain type information, and the limitation that it can only be erased to primitive or generic types.
The principles and application scenarios of Java generic type erasure
The principle of generic type erasure
In Java, generics are used to provide type-safe collections and classes. However, when compiling Java generic code, the type information is erased (eliminated) and only the type-erased bytecode is executed.
The reasons for type erasure are:
Code after type erasure
// 泛型类 class MyClass<T> { private T value; public MyClass(T value) { this.value = value; } public T getValue() { return value; } }
After compilation:
// 泛型类 (擦除后) class MyClass { private Object value; public MyClass(Object value) { this.value = value; } public Object getValue() { return value; } }
Application scenario
Type erasure has many application scenarios in actual project development, such as:
Practical case: Precautions for type erasure
Although generic type erasure provides convenience, you need to pay attention to the following matters when using it:
Object
) or other generic types. Extended reading:
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