To answer your questions specifically, yes and yes.
And I'd like to add on to what Kevin and Katherine have written as well noting that both of their answers are correct. Just thought more info can't hurt a curious mind.
Lets take a look at some of the major episodes of the novel: Holden's dream about saving the kids from the cliff, and Holden's fixation on the ducks.
Kevin is right to highlight that Holden's dream most likely represents his willingness (but ultimate inability) to save the innocence of youth. We can see this specifically through his relationship with Phoebe, his inability to complete his schooling and his episode with the call girl. Not to mention his complicated relationship with adults. Holden struggles because he cannot reconcile the expectations placed on him as a boy growing older and what he sees as his place in the world. Further complicating the issue is Holden's misplaced sense of identity. Like most youths, he is confused. At times he locates himself firmly in adulthood and at others he acts like a child and chides adults for their narrow minded worldview. Consider how Holden really only trusts his sister Phoebe and idealizes her childhood. He places innocence above everything - a recurring theme. Now, remember the passage when Holden takes his date out to dinner and he (if I remember correctly) orders a drink or tries to order a drink. He is now putting himself beyond childhood and idealizing adulthood. Holden's conflict is what I see as the major theme of the book. He is grappling with both innocence and responsibility but doesn't quite know how. This leads us to the second point I wanted to make: the one about the ducks. Holden always asks where they go and it seems like an innocuous enough question at the time, but taken as a piece of the whole we can see that it can be seen as a micro representation of Holden's teenage disillusionment. He has presumably been in a lake his whole life, and now the warm waters have frozen over and he does not know where to go.
Its a complicated structure, but one that might be made clearer if you consider the novel in a different light. Often times Salinger's novel is considered a teenage novel, sort of a YA gospel, but consider what J.D.'s own life might tell us about what made it into the book. We have to be careful about drawing one to one parallels between author and work, but I think in this case, there are certainly conclusions we can draw.
I tend to ascribe to the growing momentum behind the book as an anti-war novel. Putting aside Holden's brother's experience in the novel, Catcher might be read as Salinger's response to his own experience in WWII. Salinger was in Europe for roughly 90% of the period in which the US was involved and saw some of the deadliest fighting in Europe first hand. It is also known that he was writing while deployed. So we look at this novel through that lens and say, a novel about innocence gone and unwillingness to accept adulthood certainly fits a narrative that would have been written by a soldier.
So when JD comes home and finishes the novel, his two metaphors ring even truer. Feeling that his innocence had been robbed and unsure where to go now that the pond had frozen over he finishes the novel and begins the process of secluding himself in Cornish.
That's a SERIOUSLY abbreviated version and interpretation, and its just my interpretation, so please don't read that and think that you now have unlocked the book. Hopefully, though, this helps and understanding where the novel fits along side other mid 20th century novels might make it a more attractive read.
