java – jit会优化新对象吗？

public final class Message {
    public final String email;
    public final String escalationEmail;
    public final String assignee;
    public final String conversationId;
    public final String subject;
    public final String userId;

    public Message(String email,String escalationEmail,String assignee,String conversationId,String subject,String userId) {
        this.email = email;
        this.escalationEmail = escalationEmail;
        this.assignee = assignee;
        this.conversationId = conversationId;
        this.subject = subject;
        this.userId = userId;
    }

    public Message() {
        email = "";
        escalationEmail = "";
        assignee = "";
        conversationId = "";
        subject = "";
        userId = "";
    }

    public Message email(String e) { return new Message(e,escalationEmail,assignee,conversationId,subject,userId); }
    public Message escalationEmail(String e) { return new Message(email,e,userId); }
    public Message assignee(String a) { return new Message(email,a,userId); }
    public Message conversationId(String c) { return new Message(email,c,userId); }
    public Message subject(String s) { return new Message(email,s,userId); }
    public Message userId(String u) { return new Message(email,u); }

}

我的问题是,当像这样创建一个新对象时,优化器是否能够避免大量的对象创建：

Message m = new Message()
    .email("foo@bar.com")
    .assignee("bar@bax.com")
    .subject("subj");

相反,制作一个单独的可变构建器对象有什么好处吗？

更新2：
在阅读了apangin的答案后,我的基准无效.我会把它留在这里以供参考,如何不进行基准测试:)

更新：
我冒昧地用这段代码自己测量：

public final class Message {
public final String email;
public final String escalationEmail;
public final String assignee;
public final String conversationId;
public final String subject;
public final String userId;

public static final class MessageBuilder {
    private String email;
    private String escalationEmail;
    private String assignee;
    private String conversationId;
    private String subject;
    private String userId;

    MessageBuilder email(String e) { email = e; return this; }
    MessageBuilder escalationEmail(String e) { escalationEmail = e; return this; }
    MessageBuilder assignee(String e) { assignee = e; return this; }
    MessageBuilder conversationId(String e) { conversationId = e; return this; }
    MessageBuilder subject(String e) { subject = e; return this; }
    MessageBuilder userId(String e) { userId = e; return this; }

    public Message create() {
        return new Message(email,userId);
    }

}

public static MessageBuilder createNew() {
    return new MessageBuilder();
}

public Message(String email,String userId) {
    this.email = email;
    this.escalationEmail = escalationEmail;
    this.assignee = assignee;
    this.conversationId = conversationId;
    this.subject = subject;
    this.userId = userId;
}

public Message() {
    email = "";
    escalationEmail = "";
    assignee = "";
    conversationId = "";
    subject = "";
    userId = "";
}

public Message email(String e) { return new Message(e,userId); }
public Message escalationEmail(String e) { return new Message(email,userId); }
public Message assignee(String a) { return new Message(email,userId); }
public Message conversationId(String c) { return new Message(email,userId); }
public Message subject(String s) { return new Message(email,userId); }
public Message userId(String u) { return new Message(email,u); }


static String getString() {
    return new String("hello");
    // return "hello";
}

public static void main(String[] args) {
    int n = 1000000000;

    long before1 = System.nanoTime();

    for (int i = 0; i < n; ++i) {
        Message m = new Message()
                .email(getString())
                .assignee(getString())
                .conversationId(getString())
                .escalationEmail(getString())
                .subject(getString())
                .userId(getString());
    }

    long after1 = System.nanoTime();

    long before2 = System.nanoTime();

    for (int i = 0; i < n; ++i) {
        Message m = Message.createNew()
                .email(getString())
                .assignee(getString())
                .conversationId(getString())
                .escalationEmail(getString())
                .subject(getString())
                .userId(getString())
                .create();
    }

    long after2 = System.nanoTime();



    System.out.println("no builder  : " + (after1 - before1)/1000000000.0);
    System.out.println("with builder: " + (after2 - before2)/1000000000.0);
}


}

如果字符串参数不是新对象,那么我发现差异很大(构建器更快),但所有相同(请参阅getString中的注释代码)

在我想象的是一个更现实的场景,当所有字符串都是新对象时,差异可以忽略不计,JVM启动会导致第一个字符串变慢(我尝试了两种方式).

使用“new String”代码总共慢了许多倍(我不得不减少n),这可能表明正在进行“新消息”的某些优化,而不是“新字符串”.