Do not append char as strings

Docs > Code Analysis > Static Analysis Rules > Do not append char as strings

Metadata

ID: java-best-practices/sb-append-char

Language: Java

Severity: Warning

Category: Best Practices

Description

Do not append a string with single character to a StringBuffer. Instead, append a character type. This is better practice and results in better performance. While this is negligible if the operation occurs once, it has performance impact if done at scale.

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Non-Compliant Code Examples

public class Main{
    public static void main(String[] args){
        StringBuffer sb = new StringBuffer();
        sb.append("a");
        sb.append("abc");

        while (true) {
            sb.append("a");
        }

        for (Element e: elements) {
            sb.append("a");
        }

        if (true) {
            sb.append("a");
        } else {
            sb.append("a");
        }
    }
}

Compliant Code Examples

public class Main{
    public static void main(String[] args){
        StringBuffer sb = new StringBuffer();
        sb.append('a');
        sb.append("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" ");
    }
}