German rearmament started to take place after the Nazis took power in 1933. It was until 1934 after Hindenburg had died did Hitler become chancellor of Germany. It was stated that during the treaty of Versailles that Germany was not allowed to arm herself ever.
Adolf Hitler wanted to tear up the treaty as he believed it was a complete humiliation to the Germans. The rearmament was done very secretly but it was not until Hitler left various organisations and such as league of nations etc that other nations took notice.
The process of German rearmament was aggressively pursued during the Hitler years. But it had positive effects as the economy at the time was going through hyperinflation,unemployment and uncertainty. Hitler’s policies helped provide employment and stability but also in turn improved the lives of ordinary citizens.