CNBC's Jim Cramer has struck a "hopeful" new tune in his Wall Street outlook.

The "Mad Money" host on Monday showed a shift in his thinking about the trajectory of stocks, lightening up on his belief that the market will retest its March lows.

"I figured a retest was virtually, let's just say, inevitable ... but now I'm feeling more confident about the future," he concluded after the market closed.

There was mixed trading on Wall Street in Monday's session, with the Dow Jones and S&P 500 both sliding more than 1% and the Nasdaq Composite rising nearly half a percentage point. Coming off a strong week of trading, the blue-chip index is now up 28% from its intraday low on March 23. The S&P 500 is up 26% and the Nasdaq Composite is up 24% from their respective intraday lows that month.

"When you look at the facts, I think there's reason to be more hopeful than we have been," Cramer said. "The worst case scenario's been taken off the table, and if Apple and Google can do contact tracing that we all embrace ... while we continue to roll out more testing, the economy could reopen a lot sooner than we thought even, say, three weeks ago."

Cramer's newfound confidence was influenced by actions taken by both the federal government and private enterprise. On top of the historic multitrillion-dollar federal spending package that is now underway to mitigate economic damage of the coronavirus pandemic, he applauded the Federal Reserve's move to "go nuclear" in the latest of a string of responses from the central bank with a $2.3 trillion bond-buying program for troubled companies and local governments.

The measure could potentially help the slumping oil industry, Cramer said. OPEC and its oil-producing allies, after prodding from President Donald Trump, agreed over the weekend to a historic production cut of 9.7 million barrels per day, which the "Mad Money" host said gave American producers "some breathing room."

The Fed's initiative to buy corporate bonds will ultimately help stocks, he added.

"That means more money into stocks, especially ones with good dividend records," Cramer said. "By the way, it means that corporate earnings could be higher because companies will be able to borrow at lower rates. It means their stocks might be less expensive than they seem in the outyears."

Cramer also applauded Apple and Google, an Alphabet company, for teaming up on a contact-tracing system. The companies announced Friday they would roll out new iPhone and Android apps that will help track the spread of coronavirus and alert users who came in contact with others who have tested positive for Covid-19.

The tools are expected to be available in May.

"I think this partnership is huge. It's probably the only way we get contact tracing in America," Cramer said, adding that contact tracing is "essential to stopping this thing."