因此，我创建了两个程序（一个使用java8）来计算给定字符串中大小写字符的总数。检查执行时间后，java8的执行时间比预期的要长。是否有任何可能的方法来进一步优化这些代码以减少执行时间和复杂性？？？
代码：

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Counts
{
public static void main(String arg[])throws Exception
{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int upperCase=0, lowerCase=0;
    String str=br.readLine();
    Long startTimeMemo = System.nanoTime();
    for (int k = 0; k < str.length(); k++) {
// Check for uppercase letters.
if (Character.isUpperCase(str.charAt(k))) upperCase++;
// Check for lowercase letters.
if (Character.isLowerCase(str.charAt(k))) lowerCase++;
}

System.out.printf("%d uppercase letters and %d lowercase letters.",upperCase,lowerCase);
Long stopTimeMemo = System.nanoTime();
    System.out.println("");
    System.out.println("Memoization Time:" + (stopTimeMemo - startTimeMemo));
}
}

java8代码：

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Count2
{
    public static void main(String arg[])throws Exception
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        Long startTimeMemo = System.nanoTime();
        System.out.println(countUpperCase(str) + " " + countLowerCase(str));    
        Long stopTimeMemo = System.nanoTime();
        System.out.println("");
        System.out.println("Memoization Time:" + (stopTimeMemo - startTimeMemo));
    }
    private static long countUpperCase(String s) {
    return s.codePoints().filter(c-> c>='A' && c<='Z').count();
}

private static long countLowerCase(String s) {
    return s.codePoints().filter(c-> c>='a' && c<='z').count();
}
}