使用Java创建快速/可靠的基准测试？

public static long runTest(int times){
    long start = System.nanoTime();     
    String str = \"str\";
    for(int i=0; i<times; i++){
        str = \"str\"+i;
    }       
    return System.nanoTime()-start;     
}

Number of times ran: 5
The max time was: 1231419504 (102.85% of the average)
The min time was: 1177508466 (98.35% of the average)
The average time was: 1197291937
The difference between the max and min is: 4.58%

Activated thread activity.

Number of times ran: 5
The max time was: 3872724739 (100.82% of the average)
The min time was: 3804827995 (99.05% of the average)
The average time was: 3841216849
The difference between the max and min is: 1.78%

Running with thread activity took 320.83% as much time as running without.

    Number of times ran: 5
    The max time was: 34726168 (143.01% of the average)
    The min time was: 20889055 (86.02% of the average)
    The average time was: 24283026
    The difference between the max and min is: 66.24%

    Activated thread activity.

    Number of times ran: 5
    The max time was: 143950627 (148.83% of the average)
    The min time was: 64780554 (66.98% of the average)
    The average time was: 96719589
    The difference between the max and min is: 122.21%

    Running with thread activity took 398.3% as much time as running without.