Code reviewMediumcr-g282

Subject Unnecessary allocationLevel Mid–Senior~18 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Review this Java method that renders a CSV body from rows. It works for small exports but a customer report with ~200k rows takes minutes and spikes GC.

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Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix — specific and kind.

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Code to reviewjava

1String toCsv(List<Row> rows) {2    String out = "";3    for (Row r : rows) {4        out = out + r.id() + "," + r.name() + "," + r.amount() + "\n";5    }6    return out;7}

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