Pitfall - Calling new StringString is inefficientsuggest change
new String(String) to duplicate a string is inefficient and almost always unnecessary.
- String objects are immutable, so there is no need to copy them to protect against changes.
- In some older versions of Java,
Stringobjects can share backing arrays with other
Stringobjects. In those versions, it is possible to leak memory by creating a (small) substring of a (large) string and retaining it. However, from Java 7 onwards,
Stringbacking arrays are not shared.
In the absence of any tangible benefit, calling
new String(String) is simply wasteful:
- Making the copy takes CPU time.
- The copy uses more memory which increases the application’s memoru footprint and / or increases GC overheads.
- Operations like
hashCode()can be slower if String objects are copied.
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