Consider some of the statements Jesus made about Himself in John's gospel. He said...

"I am the bread of life" (John 6:35-51)
"I am the light of the world" (John 8:12, 9:5)
"before Abraham was born, I am!" (John 8:58)
"I am the door" (John 10:7-9)
"I am the good shepherd" (John 10:11-14)
"I am the resurrection and the life" (John 11:25)
"I am the way and the truth and the life" (John 14:6)
"I am the true vine" (John 15:1-5)
"I am he" (John 18:4-5)

These "I am" statements that Jesus was making hearkened back to a conversation Moses had with God in Exodus 3. In that chapter, God told Moses that His name was, "I AM WHO I AM." When Jesus made the "I am" statements found in John's gospel, He was doing so, in part, to reveal His true nature to those who would hear or read these words.